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iYEM'  AND  COMPLETE  TREATISE 


ON  THE 

ARTS  OF  TAMING,  CURRYING, 

AND 

LEATHER-DRESSING; 


COMPRISING  ALL  THE 


DISCOVERIES  AND  IMPROVEMENTS  MADE  IN  FRANCE,  GREAT 
BRITAIN,  AND  THE  UNITED  STATES. 

EDITED  FROM  NOTES  AND  DOCUMENTS 


MESSRS.  SALLEROU,  GROUVELLE,  DUVAL,  DESSABLES,  LABARRAQUE, 
PAYEN,  RENE,  DE  EONTENELLE,  MALEPEYRE,  ETC.  ETC. 


BY 

Professor  H.  DUSSAUCE,  Chemist, 

LATELY  OF  THE  LABORATORIES  OF  THE  FRENCH  GOVERNMENT,  VIZ.,  THE  MINING,  BOTANICAL 
GARDEN,  THE  IMPERIAL  MANUFACTURE  OF  THE  GOBELINS,  THE  CONSERVATOIRE 
IMPERIALE  OF  ARTS  AND  MANUFACTURES  ;  PROFESSOR  OF  INDUSTRIAL 
CHEMISTRY  TO  THE  POLYTECHNIC  INSTITUTE,  PARIS. 


|llnstrateb  bg  (Tfoo  punbreb  anb  (Lfoelbe  ©loob  ©ngrabings. 


SECOND  EDITION. 

PHILADELPHIA: 

HENRY  CAREY  BAIRD, 

INDUSTRIAL  PUBLISHER,  406  WALNUT  ST. 

LONDON: 

SAMPSON  LOW,  SON  &  MARSTON. 

MILTON  HOUSE,  LUDGATE  HILL. 

1867. 


Entered  according  to  Act  of  Congress,  in  the  year  1865,  by 
HENRY  CAREY  BAIRD, 

in  the  Clerk’s  Office  of  the  District  Court  of  the  United  States  in  and  for  the 
Eastern  District  of  Pennsylvania. 


PHILADELPHIA  : 

COLLINS,  PRINTER,  705  JAYNE  STREET. 


THE  GETTY  CENTER 
LIBRARY 


TO 


HON.  J.  C.  G.  KENNEDY, 

SUPERINTENDENT  OF  THE  CENSUS,  WASHINGTON,  D.  C. 

My  Dear  Sir: 

Permit  me  to  offer  to  you  the  following  work,  as 
a  very  feeble  mark  of  gratitude  for  your  unvarying 
friendship,  the  aid  you  have  extended  to  me  in  the 
preparation  of  this  volume,  and  a  sincere  testimonial 
of  the  high  respect  and  esteem  of, 

My  dear  sir, 

Your  very  obedient  servant, 

And  obliged  friend, 

H.  DUSSAUCE. 

New  Lebanon,  N.  Y.,  May  1,  1865, 


Digitized  by  the  Internet  Archive 
in  2018  with  funding  from 
Getty  Research  Institute 


https://archive.org/details/newcompletetreatOOduss_O 


PREFACE  TO  THE  SECOND  EDITION. 


The  fact  of  a  new  edition  of  The  Art  of  Tanning, 
Currying,  and  Leather-Dressing  being  called  for  in  so 
short  a  space  of  time,  would  seem  to  present  evidence 
pretty  conclusive  of  an  appreciation  by  the  trade  of  the 
labors  of  the  author.  This,  added  to  the  numerous 
testimonials  which  the  book  has  received,  convinces 
him  that  such  is  the  case,  and  that  he  has  rendered 
some  service  to  those  for  whom  he  has  written. 


New  Lebanon,  New  York, 
October  27,  1866. 


. 


I 


PREFACE. 


The  art  of  tanning  has  for  a  long  time  consisted  of  a 
series  of  empirical  operations,  notwithstanding  the  fact 
that  there  is  no  art  which  is  so  dependent  upon  certain 
fixed  principles,  and  on  which  chemistry  exerts  so  great 
an  influence.  The  processes  followed  in  manufactories, 
in  the  past,  have  varied  according  to  their  localities ; 
and  have  been  transmitted  from  father  to  son,  as  heir¬ 
looms  which  they  have  had  great  scruples  in  abandon¬ 
ing  or  even  touching.  All  new  innovations  were  viewed 
with  scorn,  and  rejected,  even  without  experiment. 
When  a  workman  had  succeeded  in  producing  good 
work,  he  believed  he  had  attained  the  ne  plus  ultra  of 
his  art,  and  he  would  have  believed  he  was  unworthy 
of  this  title,  if  he  could  have  been  persuaded  that  he 
had  yet  many  things  to  learn. 

Prejudice  and  routine  are,  nearly  always,  the  faithful 
associates  of  ignorance  and  pride,  principally  with  those 
who,  accustomed  to  manual  occupations,  look  upon  as 
useless,  and  even  banish,  as  dangerous,  those  theories 
which  alone  can  transform  an  empirical  art  into  a 
rational  one.  For  a  long  time  yet  industry  will  be  thus 
hampered,  and  the  benefits  of  science  disregarded,  and 
it  is  only  by  degrees  that  it  will  verify  the  arts. 

The  closing  years  of  the  eighteenth  century,  and  those 
of  the  nineteenth  which  have  passed,  have  changed  the 
ideas  of  manufacturers.  Those  who,  located  in  the  large 


VI 11 


PREFACE. 


cities,  have  been  benefited  by  the  help  of  science,  have 
found  imitators,  and  their  innovations  have  gradually 
spread  over  the  civilized  world. 

The  art  of  tanning  was  one  of  those  of  which  the 
theoretical  study  was  the  most  neglected;  the  first 
author  who  seems  to  have  given  his  attention  to  it  was 
M.  Desbillettes,  member  of  the  Academie  des  Sciences, 
who  in  1708  published  a  work  on  tanning,  and  in  1754 
furnished  to  the  celebrated  astronomer  Delalande  very 
good  materials  for  his  encyclopedical  work  on  tanning 
and  currying.  The  researches  of  M.  Delalande  give 
exact  processes,  and  a  true  picture  of  the  method  then 
followed.  Guided  by  these  works,  several  experi¬ 
menters,  amongst  whom  we  may  mention  MacBride, 
Pfeffer,  and  St.  Beal,  published  processes  for  the  im¬ 
provement  of  the  art  of  tanning,  which,  if  they  were  not 
completely  adopted,  at  least  presented  useful  views. 
Such  was  the  position  of  this  art  when  one  of  the  fellow- 
laborers  of  the  illustrious  Lavoisier,  M.  Seguin,  proposed 
in  1774  to  tan  hides  in  from  one  to  two  or  three  months. 
The  quality  of  the  leather  did  not,  however,  correspond 
with  the  quickness  of  the  operation.  Notwithstanding 
this  failure,  the  works  of  this  chemist  exercised  a  power¬ 
ful  influence  on  the  progress  of  the  art,  principally  after 
his  chemical  studies  of  tannin.  Several  English  chemists 
adopted  the  ideas  of  Seguin,  while  others  modified  them, 
and  discovered  new  processes.  The  art  of  tanning 
ceased  to  be  an  entirely  empirical  one,  when  chemistry 
began  to  help  it,  by  the  different  works  and  researches 
of  Gettliffe,  the  father  and  the  son,  Monier  and  Ray, 
Paillard  Vaillant,  Grouvelle,  Duval  Duval,  Salleron, 
Dolphus,  Fischerstrcem,  Payen,  Kartsoff,  Didier,  J. 
Smith  and  J.  Thomas,  Trempe,  Nenory,  Tournal,  Curan- 
deau,  Conche,  Poul,  Labarraque,  Leprieur,  Bagnal, 
Weldon,  Dessables,  Delbut,  Boetger,  Boudet,  Berlingue, 


PREFACE. 


IX 


Berendorf,  Cox,  Beringer,  Vauquelin,  Ogereau,  Spils- 
burg,  Ivampfmeyer,  Turnbull,  Snyder,  and  others. 

We  have  here  given  the  important  facts,  and  the 
principles  established  by  these  investigators  and  authors 
on  this  subject. 

While  gladly  and  fully  acknowledging  our  indebted¬ 
ness  for  much  matter  to  Professor  Morfit’s  edition  of  De 
Fontenelle  and  Malepeyre’s  treatise,  prepared  some  years 
since  for  the  publisher  of  this  volume,  the  present  publi¬ 
cation  may  lay  claim  to  being  a  new  work,  by  reason  as 
well  of  the  numerous  additions  as  by  the  considerable 
and  important  changes  and  improvements  we  have  made 
throughout  it. 

We  take  great  pleasure  in  acknowledging  our  indebted¬ 
ness  to  those  who  have  so  kindly  assisted  us  in  our 
researches,  and  would  express  our  particular  obligations 
to  the  Hon.  J.  C.  G.  Kennedy,  Hon.  D.  P.  Holloway, 
D.  Aldrich,  Esq.,  Hatch,  the  Shaker  Society  of  New 
Lebanon,  etc.  We  have  taken  several  articles  from  the 
two  most  important  industrial  publications  of  this 
country,  the  Shoe  and  Leather  Reporter  and  the  Scientific 
American ,  and  desire  here  to  acknowledge  our  obliga¬ 
tions  to  them.  We  have  consulted  nearly  all  foreign 
and  home  publications;  in  a  word,  we  have  neglected 
neither  pains  nor  trouble  to  make  this  work  a  standard 
one.  We  trust  it  will  answer  the  purposes  for  which  it 
is  designed,  and  our  reward  will  then  be  found  in  the 
services  we  have  rendered  to  the  profession. 

New  Lebanon,  New  York, 

May  16,  1865. 


CONTENTS 


PAGE 

Introduction  .  . . . 17 

Leather  produced  in  the  United  States  in  1850  and  i860  .....  20 

Origin  and  Development  of  the  Art  of  Tanning  ......  23 

Parchment  Dressing  .  . . . 29 


PART  I. 

CHEMISTRY  OF  TANNING. 

SECTION  I. 

TAN  AND  TANNIN. 

CHAPTER  I.  Pure  Tannin,  34. — Chemical  properties,  34 — Composition,  38 — Pre¬ 
paration,  39. 

CHAPTER  II.  Impure  Tannin,  41. — Chemical  properties  of  impure  tannin  ;  Pre¬ 
paration  ;  Varieties  in  the  impure  tannin,  41 — Preparation  of  tannin  from 
nutgalls,  43 — Proust’s  process,  43 — Deyeux’s  process,  43 — Dize’s  process,  44 — 
Merat-Guillot’s  process,  44 — Bouillon-Legrange’s  process,  44 — Tromsdorff’s 
process,  44 — Serturner’s  process,  45 — Varieties  of  impure  tannin,  45 — Tannin 
of  catechu,  46 — Tannin  of  hark  of  trees;  Sumach;  Kino,  46 — Tannin  which 
forms  a  bluish-black  precipitate  in  solutions  of  a  sesqui-salt  of  iron,  47 — Tan¬ 
nin  which  forms  a  green  precipitate  in  the  dissolution  of  iron,  47. 

CHAPTER  III.  Artificial  Tannin,  47. — Properties,  47 — Composition,  48 — First 
variety,  49 — Second  variety,  49 — Third  variety,  49 — Preparation  of  a  tannin 
from  turf,  49. 

CHAPTER  IV.  Tannin  from  Various  Sources,  54. 

CHAPTER  V.  Gallic  and  Ellagic  Acids,  51. — Gallic  acid,  51 — Preparation. 
52 — Scheele’s  process,  52 — Fiedler’s  process,  52 — Braconnot’s  process,  52 — 
Ure’s  process,  52 — Properties,  54 — Composition,  56 — Ellagic  acid,  56. 


CHAPTER  VI.  Extractive,  58. 


Xll 


CONTENTS. 


SECTION  II. 

TANNING  MATERIALS.  ' 

CHAPTER  VTI.  Tanning  Saps  ;  Tanning  Juices  ;  Kino;  Catechu,  62. — Tan¬ 
ning  saps,  62 — Sap  of  the  beech  tree,  63 — Tanning  juices,  64 — Kino,  64 — 
African  kino,  65 — Jamaica  kino,  65 — South  American,  Columbia,  or  Caraccas 
kino,  65 — Catechu,  66 — Cake  catechu,  67 — Pegu  catechu,  67 — Bengal  catechu, 
67 — Bombay  catechu,  68 — Gambir,  68 — Areca  catechu,  68. 

CHAPTER  VIII.  Excrescences  Containing  Tannin,  69. — Nutgalls,  69. 

CHAPTER  IX.  Leaves;  Tea;  Flowers  and  Fruits:  Seeds  and  Bulbs,  71. 
— Leaves,  71 — List  of  tanning  leaves,  71 — Tea,  7.3 — Flowers  and  fruits,  74 — 
Valonia,  74 — Divi-divi,  75 — Of  tanning  flowers  and  flower  tops,  76 — Seeds  and 
bulbs  suitable  for  tanning,  77. 

CHAPTER  X.  Woods;  Roots;  Barks,  77. — Woods,  77 — Roots,  78 — Dentelaria, 
78 — Malefern,  78 — Rhatany,  78 — Marsh  rosemary,  79 — Barks,  79 — Cinnamon, 
82 — Sassafras,  83 — Birch  bark,  84 — Chestnut  bark,  84 — Horse-chestnut,  84 — 
Beech  bark,  84 — Lombardy  poplar  bark,  84 — Black  thorn  bark,  84 — Pome¬ 
granate  bark,  84 — Ash  bark.  84 — Elm  bark,  85 — Cinchona  bark,  85 — Poison 
oak,  85 — Sumach,  85 — Willow  bark,  87 — Tamarisk,  87 — Hemlock  bark,  87. 

CHAPTER  XI.  Oak  Barks,  88. — European  oaks,  88 — American  oaks,  90. 

CHAPTER  XII.  Barking  of  the  Trees,  92. — Parts  of  the  bark  containing  the 
most  tannin,  92 — Age  of  the  trees  relatively  to  the  richness  of  the  barks  in 
tannin,  92 — Barking  and  the  most  convenient  time  for  it,  93 — Influence  of 
seasons  and  place  at  the  time  of  barking  on  the  richness  in  tannin,  94 — 
Decrease  in  weight  of  smooth  bark  when  exposed  to  the  air,  94. 

CHAPTER  XIII.  Plants  Containing  Tannin  used  as  Substitutes  for  Oak 
Barks,  96. 

CHAPTER  XIV.  Methods  of  Estimating  the  Tanning  Power  of  Astringent 
Substances,  101. — Examination  of  barks,  101 — Chemical  examination,  101 — 
R.  Warrington’s  process,  102 — Davy’s  process,  102 — Bell  Stephens’  process, 
103 — Muller's  process,  103 — Method  of  Dr.  D.  W.  Gerland,  107 — Table  of  the 
quantities  of  tannin  contained  in  the  principal  tanning  substances,  110 — Com¬ 
parative  quantities  of  different  tanning  substances  necessary  to  tan  an  equal 
quantity  of  leather,  112. 

CHAPTER  XV.  Tan  or  Powdered  Oak-Bark,  112. — Bagnall’s  machine  for 
chopping  bark  and  fleshing  hides,  114-r Weldon’s  mill  for  grinding  oak  bark, 
118 — Farcott’s  bark-chopping  machine,  121 — Bourgeois’s  bark  mill,  124 — 
Lespinasse’s  bark  mill,  127 — Birely’s  mill,  133. 

CHAPTER  XVI.  Tanning  Extracts,  134. — J.  Connel’s  concentrated  extract,  134 
— A.  Steers’s  process,  135 — The  Author’s  method,  136. 

SECTION  III. 

SKIN. 

CHAPTER  XVII.  Proximate  Principles  of  Leather;  Structure  of  the 
Skin,  138. — Proximate  principles  of  leather,  138 — Structure  of  the  skin,  138 
— Behavior  of  the  epidermis  and  cutis  with  reagents,  139. 


CONTENTS. 


Xlll 


CHAPTER  XVIII.  Constitution  of  the  Skin,  141. — Composition  of  the  skin,  141 
— Fibrin,  141 — Gelatine,  143 — Albumen,  144. 

CHAPTER  XIX.  The  Proper  Treatment  op  Hides  and  Skins;  Kinds  op 
Skins  Suitable  for  Tanning  ;  Salting  op  the  Hides,  145. — Ox-hides,  148 
— Calves’  skins  and  kips,  149 — Horse-hides,  149 — Sheep-skins,  150 — Goat¬ 
skins,  150 — Deer-skins,  151 — Hog  or  pig-skins,  151 — Seal-skins,  151 — Porpoise- 
skins,  152 — Hippopotamus  hides,  152 — Mode  of  salting  hides,  152. 


PART  II. 

TANNING. 

SECTION  IV. 

PRELIMINARY  TREATMENT  OP  SKINS. 

CHAPTER  XX.  Washing  and  Soaking,  153. — Soaking  of  foreign  hides,  156. 

CHAPTER  XXI.  Influence  op  the  Water  upon  the  Quality  op  Leather,  160 
— Rain  water,  161 — Snow  water,  161 — Spring  water,  161 — River  water,  161 — 
Lake  water,  161 — Marsh  water,  161 — Well  water,  161. 

CHAPTER  XXII.  Swelling  or  Raising  op  the  Hides. — Lime  process,  163. 

CHAPTER  XXIII.  Stacking  of  the  Hides,  166. 

CHAPTER  XXIV.  Inconvenience  op  the  Lime  Process,  168. 

CHAPTER  XXV.  Method  of  Raising  by  Acid,  169. 

CHAPTER  XXVI.  Depilatign  by  Steam,  170. 

CHAPTER  XXVII.  Depilation  by  Caustic  Soda,  170. 

i 

CHAPTER  XXVIII.  Depilation  by  Sulphuret  op  Calcium  and  Soda,  171. — 
Preparation  of  the  hydrosulphate  of  lime,  172. 

CHAPTER  XXIX.  Cool  Sweating  Process,  174. 

CHAPTER  XXX.  Raising  by  Barley  Dressing,  176. 

CHAPTER  XXXI.  Wallachia  Leather,  183. — Method  of  working  the  dressings, 
186 — Bran  dressing,  188 — Decomposition  of  the  white  dressings,  189. 

CHAPTER  XXXII.  Rye  Dressing,  or  Transylvania  Leather,  190. 

CHAPTER  XXXIII.  Raising  by  Sour  Tan-Liquor,  190. — Preparation  of  the  tan- 
liquor,  195. 

CHAPTER  XXXIV.  Raising  by  Yeast,  197. 

CHAPTER  XXXV.  Working  on  the  Beam,  197. 


XIV 


CONTENTS. 


SECTION  V. 

TANNING  PROCESS. 

CHAPTER  XXXVI.  Tan  Vats,  199.— Wheat’s  patent  vat,  203. 

CHAPTER  XXXVII.  Heald’s  Apparatus  for  Tanning  Hides,  206. 

CHAPTER  XXXVIII.  Time  Necessary-  for  Tanning,  209. 

CHAPTER  XXXIX.  Proportions  of  the  Bark  Used,  210. 

CHAPTER  XL.  Drying  of  the  Leather,  211. 

CHAPTER  XLI.  Beating  of  the  Leather,  214. 

CHAPTER  XLII.  Beating  and  Rolling  by  Machinery',  215. — Debergue’s  ma¬ 
chine,  216 — Elotard  and  Delbut’s  machine,  215 — Berendorf’s  machine  for 
pressing  hides,  225 — Cox’s  machine,  230 — Wiltse’s  rolling  table,  232 — Seguin's 
machine  to  flesh  and  gloss  leather,  234. 

CHAPTER  XLIII.  Tissue  and  Quality  of  Leathers — their  Defects  and  the 
way  of  ascertaining  them,  234. — Action  of  frost  on  leather,  236. 

CHAPTER  XLIV.  Belt  Leather,  238. — How  to  manufacture  cow-leather  into 
uppers  of  a  superior  quality,  241. 

CHAPTER  XLV.  Tanning  of  Calf-Skins,  244. 

CHAPTER  XLVI.  Tanning  of  Calf-Skins  for  the  Preparation  of  Waxed 
Calf-Skins.  By  M.  Rene,  245. — Classification  of  untanned  calf  skins,  247 
— Washings,  247 — Liming,  248 — Salted  skins,  250 — Dried  calf-skins,  250 — 
Dry  calf-skins  from  foreign  countries,  251 — River  work,  252 — Operation 
first,  353 — Treatment  with  strong  liquors,  265 — Dressing,  269. 

CHAPTER  XLVII.  Tanningof  Goat  and  Sheep-Skins,  270. — Bleaching  of  goat¬ 
skins,  273 — Coloring  of  whole  sheep-skins,  274. 

CHAPTER  XLVIII.  Morocco  Leather  Dressing — Cordovan  Leather,  276. 

CHAPTER  XLIX.  Tanning  of  Horse-Hides,  281. 

CHAPTER  L.  Tanningof  Different  Skins,  282. 

CHAPTER  LI.  Tanning  of  the  Skins  of  Sheep’s  Legs  for  making  Tubes 
without  Suture,  for  covering  the  Cylinders  used  in  Cotton  and  Wool 
Spinning,  283. — Leather  bottles,  338. 

CHAPTER  LII.  Red  Leather,  284. 

CHAPTER  LIII.  Danish  Process,  285. 

CHAPTER  LIV.  Chemical  Theory  of  Tanning,  285. — Chemical  researches  on 
the  art  of  tanning.  By  M.  Knapp,  289. 


SECTION  YI. 

IMPROVED  PROCESS. 

CHAPTER  LV.  Sf.gcin’s  Process,  295. 

CHAPTER  LVI.  Process  of  Preparing  Glossed  Leather  before  the  Tan¬ 
ning  Operation,  296. — Details  of  the  work  of  the  preparation  of  the  leather, 
296 — Hides,  296 — Smelting,  296 — Liming,  296 — Cleaning,  296 — Description  of 
the  apparatus,  297 — Tanning,  298. 


CONTENTS, 


XV 


CHAPTER  LVII.  Tanning  with  Myrtle,  299. 

CHAPTER  LVIII.  Tanning  with  Grape-Skins,  299. 

CHAPTER  LIX.  Tanning  with  Statice,  300. 

CHAPTER  LX.  Leprieur’s  Tanning  Process,  301. — Sugar  of  lead  bath,  301 — 
Tan  liquor  baths,  302 — First  series  of  infusions,  302 — Second  series  of  in. 
fusions,  303 — Tanning  in  the  vats,  304 — Quantities  of  tan  employed  for  tan¬ 
ning  220  lbs.  of  leather,  306. 

CHAPTER  LXI.  D’Arcet’s  Process  by  the  Sulphate  op  Sesqui-Oxide  of 
Iron,  306. 

CHAPTER  LXII.  Newton's  Process,  307. 

CHAPTER  LXIII.  Preparing  Dry  Flint  Hides,  308. 

CHAPTER  LXIV.  Process  of  Tanning  of  H.  C.  Jennings,  310. 

CHAPTER  LXV.  Berenger  and  Sterlingue’s  Process,  311. 

CHAPTER  LXVI.  Corniquet’s  Process  of  Substituting  the  Fruit  of  the 
Pine  for  the  Bark  in  Tanning,  317. 

CHAPTER  LXVII.  Vauquelin’s  Process,  318. — Description  of  the  figures, 
320. 

CHAPTER  LXVIII.  Ogereau’s  Process,  327. 

SECTION  YII. 

AMERICAN,  ENGLISH,  AND  OTHER  PROCESSES. 

CHAPTER  LXIX.  Process  of  Tanning  with  a  Decoction  of  Oak  Bark,  328. 

CHAPTER  LXX.  Desmond’s  Process,  329. 

CHAPTER  LXXI.  J.  Burbidge’s  Process  with  Extract  of  Oak  Bark  and 
Catechu,  330. 

CHAPTER  LXXII.  Kleman’s  Process,  331. 

CHAPTER  LXXIII.  Spilsbury’s  Process  by  Pressure,  332. 

CHAPTER  LXXIV.  M.  W.  Drake’s  Process,  334. 

CHAPTER  LXXV.  Rotch’s  Quick  Process  of  Tanning  Leather,  335. 

CHAPTER  LXXVI.  J.  P.  Knowlis’s  Process,  337. 

CHAPTER  LXXVII.  Tanning  Apparatus  of  D.  Aldrich,  of  St.  Louis,  Mo., 

338. 

CHAPTER  LXXVIII.  Tanning  Wheel  of  V.  E.  Rusco,  347. 

CHAPTER  LXXIX.  New  Mode  of  Tanning  Skins  by  a  Liquor  of  Tar  and 
Soot,  351. — Preparation  of  the  tan  liquor,  351 — Preparation  of  the  soot 
liquor,  351 — Preparation  of  the  skins  intended  for  leather,  352 — Preparation 
of  leather  for  soles,  352. 

CHAPTER  LXXX.  Indian  Method  of  Preparing  Elk-hides,  353. 

CHAPTER  LXXXI.  Hatch’s  Process  of  Tanning,  called  Illinois  French 
Tanning,  353. 

CHAPTER  LXXXII.  Irish  Process,  357. 

CHAPTER  LXXXIII.  Process  of  Manufacturing  Leather  called  Cuirs  a 
Muron,  358. 


XVI 


CONTENTS, 


CHAPTER  LXXXIV.  Kalmucks’  Process,  359. 

CHAPTER  LXXXV.  Leather  Manufacture  in  Turkey,  361. 

CHAPTER  LXXXVI.  J.  Hannoye’s  Process,  365. 

CHAPTER  LXXXVII.  M.  Nossiter’s  Process,  368. 

CHAPTER  LXXXVIII.  Squire’s  Process,  372. 

CHAPTER  LXXXIX.  English  Process  for  Tanning  Nets,  Sails,  And  Ropes, 
373. 

CHAPTER  XC.  Experiments  in  the  Tanning  of  Calf-Skins  with  Tan,  Divi- 
Diyi,  Catechu,  and  Elecampane  Bark,  374. — Oak  bark,  374 — Divi-divi, 
375 — Catechu  (terra  japonica),  375 — Elecampane  bark,  375. 

CHAPTER  XCI.  Tanning  Hides,  by  J.  W.  Johnson,  376. 

CHAPTER  XCII.  Turnbull’s  Process,  377. 

CHAPTER  XCIII.  S.  Snyder’s  Process,  381. 

CHAPTER  XCIV.  H.  Hibbard’s  Process,  382. — Preparation  of  the  skins,  383 — 
Composition  for  tanning,  383. 

CHAPTER  XCV.  Hemlock  Tanning,  384. — Process  of  tanning  as  performed  at 
the  Shaker  Tannery,  New  Lebanon,  N.  Y.,  386. 

CHAPTER  XCVI.  Halvorson’s  Process  for  Rendering  Hides  Hard  and 
Transparent,  389. 

CHAPTER  XCVII.  Tawing,  390. — Kid  leather,  390 — Imitation  kid,  392. 

CHAPTER  XCVIII.  The  Best  Method  of  Tanning  Small  Lamb-Skins  called 
Chamois,  and  especially  White  Peltry  for  Furriers,  393. 

CHAPTER  XCIX.  New  Method  of  Coloring  White  Tawed  Leather,  395. 

CHAPTER  C.  Quick  Tanning,  396.— M.  D.  Kennedy's  process,  398 — I.  L.  Wells’ 
process,  399 — J.  Cochran’s  process,  399 — W.  R.  Webster’s  process,  399 — 
Bunting’s  process,  400 — Thompson’s  process,  400 — L.  Robinson’s  process,  400 
— T.  G.  Eggleston’s  process,  400 — A.  Dietz’s  process,  401 — P.  Daniel’s  process, 

402 —  D.  Needham’s  process,  402 — R.  Harper’s  process,  403 — A.  Hill's  process, 

403 —  J.  Nuessley’s  process,  404 — M.  A.  Bell’s  process,  404 — Blet’s  process, 

404 —  Baron’s  process,  405 — Quick  process,  405—  Guiot’s  process,  406. 

CHAPTER  Cl.  Residues  and  Products  of  Tanneries,  407. 


PART  III. 

CURRYING. 


SECTION  Till. 


GENERAL  WORK  OF  THE  CURRIER. 


CHAPTER  CII. 
CHAPTER  CIII. 
CHAPTER  CIV. 
CHAPTER  CV. 
CHAPTER  CVI. 


Dipping,  410. 

Shaving,  413. 

Pommeling,  414. 

Stretching,  415. 

Working  With  the  Round  Knife,  417 


CONTENTS, 


XVII 


CHAPTER  CVII.  Preparation  of  Stretched  Leather,  418. 

CHAPTER  CVIII.  Preparation  of  Sleeked  Leather,  420. 

CHAPTER  CIX.  Comparison  of  Sleek  Leather  with  Alum-Dressed  Leather, 
423. 

CHAPTER  CX.  Tallowed  or  Grained  Leather,  424. — Grain  black  ;  liow  to 
improve  it,  426. 

CHAPTER  CXI.  Water  Leather,  429. 

CHAPTER  CXII.  Oil  Leather,  429. — Oiled  leather,  423. 

CHAPTER  CXIII.  Waxed  Leather,  435. 

CHAPTER  CXIV.  English  Hides,  436. 

CHAPTER  CXV.  White  Leather  and  Common  Russet,  438. 

CHAPTER  CXVI.  Currying  of  Calf-Skins — Oiled  Calf-Skins,  439. 
CHAPTER  CXVII.  Tallowed  Calf-Skins,  441. 

CHAPTER  CXVIII.  English  Calf-Skins,  441. 

CHAPTER  CXIX.  Waxed  Calf-Skins,  442. — Fleshing  and  shaving,  442 — Bleach¬ 
ing  or  whitening,  456 — Graining,  448 — Mode  of  making  the  blacking  and  its 
applications,  460 — Finishing,  462. 

CHAPTER  CXX.  Grained  Calf-Skins,  468. 

CHAPTER  CXXI.  Calf-Skin  Leather  for  Belts,  468. 

CHAPTER  CXXII.  Greasing  Tanned  Hides,  469. 

CHAPTER  CXXIII.  Saturation  of  Leather  with  Grease,  473. 

CHAPTER  CXXIV.  Calf-Skins  Called  Alumed  Skins,  475. 

CHAPTER  CXXV.  E.  Jahkel’s  Process  for  Manufacturing  Leather  for 
Harness-Makers,  479. 

CHAPTER  CXXVI.  Currying  of  Goat-Skins,  481. 

SECTION  IX. 

RUSSIA  LEATHER. 

CHAPTER  CXXVII.  Process  of  Manufacturing  Russia  Leather,  483. 

CHAPTER  CXXVIII.  Distillation  of  the  Empyreumatic  Oil  of  Birch-Bark 
for  Russia  Leather,  486. — Fischerstroern’s  process,  486 — Another  process, 
486 — Grouvelle  and  Duval-Duval’s  process,  487 — Payen’s  process,  487. 

CHAPTER  CXXIX.  Nature  of  the  Odoriferous  Substances  of  the  Birch- 
Tree  Bark,  489. 

CHAPTER  CXXX.  Preparation  of  Russia  Leather,  489. 

CHAPTER  CXXXI.  Coloring  of  Red  Russia  Leather,  490. 

CHAPTER  CXXXIT.  Extract  from  a  Memoir  on  the  Process  of  Tanning 
Skins  in  Russia  by  the  Count  of  Kartsoff,  492. 

CHAPTER  CXXXIII.  Red  Leather,  496. 

CHAPTER  CXXXIV.  Shagreen  and  Parchment,  497. — Shagreen,  497. 
CHAPTER  CXXXV.  Parchment,  499. 

B 


xvm 


CONTENTS, 


SECTION  X. 

PATENT  LEATHER, 

CHAPTER  CXXXVI.  Fabrication  of  the  Patent  Leather,  503. 

CHAPTER  CXXXVII.  Didier’s  Process,  505. — White  polished  leather,  506 — 
Red  polished  leather,  506 — Blue  polished  leather,  506 — Yellow  polished  leather, 
506 — Polished  leather  of  leather  color,  506 — Black  lacquer  for  shoes  and 
leather  work,  506 — Process  for  varnishing  leather  for  belts,  Ac.,  507. 

SECTION  XI. 

WATER-PROOF  LEATHER. 

CHAPTER  CXXXVIII.  Process  of  J.  Smith  and  J.  Thomas,  508. 

CHAPTER  CXXXIX.  Nenory’s  Preparation  to  render  Leather  Water¬ 
proof  and  Impervious,  508. — Preparation  of  siccative  oil,  508— -Preparation 
of  the  elastic  gum,  509 — Preparation  of  the  compound,  509 — Process  of  using 
the  composition,  509. 

CHAPTER  CXL.  Dean’s  Process  for  rendering  Leather  Impervious,  509. 
— First  composition,  509 — Second  composition,  510 — Third  composition,  510 
— Fourth  composition,  510 — Application  of  the  composition,  510. 

CHAPTER  CXLI.  Different  Processes,  511. — Cheap  method  of  making  leather 
water-proof,  511 — Jenning’s  process,  511. 


PART  IY. 

HUNGARY  LEATHER. 

SECTION  XII. 

CHAPTER  CXLII.  Grease  and  Animal  Oils,  514. — Lard,  515 — Mutton  suet, 
515 — Beef  tallow,  515 — Medullary  beef  talIow^515 — Fish  oils,  516 — Dolphin 
oil,  516 — Porpoise  oil,  516 — Different  fish  oils,  516 — Process  by  which  to  give 
to  a  mixture  of  different  oils  and  greases  the  properties  of  fish  oils,  517 — Pro¬ 
cess  for  rendering  vegetable  oils  fit  to  take  the  place  of  fish  oils,  517. 

CHAPTER  CXLIII.  River  Work,  517. 

CHAPTER  CXLIV.  Aluming  the  Hides,  518. 

CHAPTER  CXLV.  Second  Aluming,  520. 

CHAPTER  CXLYI.  Drying  and  Stretching,  520. 

CHAPTER  CXLVII.  Treading  out  the  Hides,  521. 

CHAPTER  CXLVIII.  Tallowing,  522. 

CHAPTER  CXLIX.  Flaming,  526. 

CHAPTER  CL.  Exposure  to  the  Air,  527. 

CHAPTER  CLI.  Weighing — Marking — Piling,  527. 


CONTENTS, 


XIX 


CHAPTER  CLII.  Hungary  Leather  made  of  Cow  and  Calf  Skins,  528. 
CHAPTER  CLIII.  Hungary  Leather  made  of  Horse-Hides,  529. 

CHAPTER  CLIV.  M.  Kresse’s  Process  of  Preparing  Black  Hungary  Lea¬ 
ther,  530. 

CHAPTER  CLY.  Defects  in  the  Quality  of  Hungary  Leather,  531. 
CHAPTER  CLVI.  Uses  of  Hungary  Leather,  532. 

CHAPTER  CLVII.  Improvement  of  M.  Curandeau,  533. 


.  PART  V. 

GUT-DRESSING. 

SECTION  XIII. 

PREPARATION  OF  THE  INTESTINES  OF  CATTLE. 

CHAPTER  CLVIII.  Operations  followed  in  the  Preparation  of  Intestines 
of  Cattle,  534. — Description  of  the  workshop,  534 — Scouring,  535 — Turning 
over,  535 — Putrid  fermentation,  536 — Scraping,  536 — Washing,  536 — Insuffla¬ 
tion,  536 — Desiccation,  537 — Disinsufflation,  537 — Measuring,  537 — Sulphura- 
tion,  537 — Folding,  537. 

CHAPTER  CLIX.  Disinfection  of  the  Workshops — Mode  of  Suppressing 
Putrefaction,  538. 

CHAPTER  CLX.  Gold-Beater’s  Skin,  538. 

CHAPTER  CLXI.  Lathe-Cords,  539. 

CHAPTER  CLXII.  Manufacture  of  Cords  from  the  Intestines  of  Sheep, 
540. 

CHAPTER  CLXIII.  Different  Cords,  542. — Cords  for  rackets,  542 — Whip  cords, 
542— Hatter’s  cords  for  bowstrings,  542 — Clockmaker’s  cord,  543. 

CHAPTER  CLXIV.  Cords  for  Musical  Instrument  Strings,  543. 


PART  VI. 

DIFFERENT  KINDS  OF  APPARATUS  USED  BY  LEATHER 
MANUFACTURERS. 

CHAPTER  CLXV.  Improved  Machine  for  Rolling  Green  or  Wet  Leather, 
546. — Operation,  552. 

CHAPTER  CLXVI.  Machines  for  Finishing  Leather,  552. 

CHAPTER  CLXVII.  Leather-Polishing  Machine,  563. 

CHAPTER  CLXVIII.  Jacob  Perkins’s  Machine  for  Pommeling  and  Grain¬ 
ing  Leather,  565. 

CHAPTER  CLXIX.  Nisbet’s  Grounding  and  Pumicing  Machine,  568. 


XX 


CONTENTS. 


CHAPTER  CLXX.  Embossing  op  Leather,  571. — Bernheim  and  Labouriau’s 
process,  571 — F.  W.  East’s  process,  574. 

CHAPTER  CLXXI.  Degrand’s  Machine  for  Splitting  and  Shaving  Leather, 
575. 

CHAPTER  CLXXII.  Giraudon’s  Machine  for  Splitting  and  Shaving  Lea¬ 
ther,  577. 

CHAPTER  CLXXIII.  Machines  for  Splitting  and  Shaving  Leather,  582  — 
Richardson’s  machine,  582 — Seguin’s  shaving  and  smoothing  machine,  583 — 
Chapman’s  improved  leather-splitting  machine,  584 — Introduction  of  splitting 
machine  into  German  heavy  and  upper  leather  tanneries,  586. 


THE 


ARTS  OF  TANNING,  CURRYING, 

AND 

LEATHER- DRESSING. 


INTRODUCTION. 

The  art  of  tanning  is  that  by  which  animal  skins  are 
converted  into  leather ,  a  product  possessing  certain  char¬ 
acteristic  properties,  differing  entirely  from  those  of  the 
same  material,  and  eminently  adapting  it  to  the  useful 
purposes  for  which  it  is  employed.  Those  properties 
are  of  a  physical  nature,  and  vary  with  the  kind  of  skin 
employed,  and  the  modification  of  the  process  which  it 
undergoes.  Chemically  considered,  however,  leather 
proper,  whatever  its  kind,  is  a  definite  compound  of  tan¬ 
nin  and  gelatine,  possessing  the  all-desirable  requisites  of 
durability,  pliability,  inalterability,  insolubility  in  water, 
and  great  power  of  resisting  the  action  of  chemical  re¬ 
agents.  When  mineral  or  earthy  substances  are  used  as 
the  leather-making  agents,  the  result  is  a  compound  of 
gelatine  with  the  base  employed,  and  is  more  or  less  in¬ 
destructible,  according  to  the  nature  of  the  material  and 
the  circumstances  under  which  the  combination  takes 
place. 

It  is  much  to  be  regretted  that  so  little  has  been  done 
by  science  for  the  improvement  of  the  art  of  tanning, 
although  many  years  have  elapsed  since  the  chemical 
union  of  tannin  and  gelatine  was  first  demonstrated ; 
discovery  has  not  yet  shown  that  abundant  fruitfulness 
which  it  seemed  to  promise  positively  and  almost  imme¬ 
diately.  It  is  true  that  a  long  step  forward  has  been 
made,  but  has  it  not  been  effected  by  automatic  rather 
2 


18 


INTRODUCTION. 


than  by  natural  movement'?  by  mechanical  force  rather 
than  by  scientific  combinations  ?  In  a  word,  is  not  the 
art  of  tanning  in  America  almost  as  strictly  empirical 
now  as  it  ever  was ?  If  the  production  of  our  tanneries 
has  been  increased  and  the  time  of  their  work  shortened, 
it  is  not  owing  so  much  to  the  introduction  of  new  prin¬ 
ciples  and  to  scientific  theorizing  as  to  the  use  of  im¬ 
proved  apparatus  for  facilitating  old  processes.  Take 
away  our  bark  and  hide-mills,  improved  vats,  and  other 
constructions,  and  our  steam-power,  turn  us  out  of  doors 
to  work  amongst  the  rude  contrivances  of  a  hundred 
years  ago,  and  would  the  result  of  our  labor  show  an 
extraordinary  gain  over  that  of  our  predecessors  ? 

The  modern  appliances,  of  which  American  tanners 
boast,  are  certainly  ingenious  and  praiseworthy,  and  we 
would  not  be  understood  to  depreciate  their  importance, 
or  to  slight  the  intelligent  enterprise  of  which  they  are 
the  offspring.  But  we  wish  to  record  and  to  direct 
attention  to  the  fact  that  in  tanning,  as  in  other  occupa¬ 
tions,  the  habits  of  the  American  mind  lead  to  invention 
rather  than  to  discovery.  Now,  in  many  other  occupa¬ 
tions  the  fertile  invention  of  our  countrymen  may  insure 
perfect  success ;  but  in  tanning  it  cannot ;  for  here  in¬ 
vention  is  only  the  servant  of  discovery,  and  must  follow 
instead  of  preceding  it.  It  is  skill,  not  force,  chemical 
combination,  not  steam-power,  which  is  principally  to 
accelerate  and  cheapen  the  process  of  tanning ;  and  the 
sooner  the  trade  acts  on  this  conviction,  which  every 
day’s  experience  ought  to  strengthen,  the  better.  If  they 
can  supersede  our  present  machinery  by  the  discovery 
of  more  effective  and  economical  methods,  it  will  furnish 
causes  for  congratulation  and  none  for  mourning.  They 
must  aim  to  be  good  chemists  as  they  are  already  good 
mechanics.  With  the  analytical  taste  of  the  French  and 
Germans  superadded  to  their  over-ingenuity  and  energy, 
what  results  might  not  be  expected  from  their  studies? 
The  field  to  be  explored  is  a  broad  one.  Long  as  the 
art  of  tanning  has  been  known  to  the  world,  not  one 
step  in  its  practice  seems  to  be  complete.  There  is  still 
room  for  inquiry  after  tanning  materials,  and  still  a 


INTRODUCTION. 


19 


doubt  whether  tannin,  or  what  is  equivalent  to  tannin, 
may  not  be  produced  in  quantity  by  artificial  means. 
The  hide  itself  should  be  examined  and  analyzed  at 
every  stage  of  its  manufacture.  Its  structure  cannot  be 
too  minutely  scrutinized  ;  its  preliminary  preparation  is 
a  problem;  the  nature  of  gelatine  is  a  study;  the  manu¬ 
facture  of  ooze,  simple  as  it  appears,  is  not  uniform;  the 
proper  consistency  and  strength  of  the  liquor  is  yet  to 
be  graduated  and  fixed.  Most  of  all,  the  union  of  the 
tannin  and  the  gelatine  in  the  interior  fibres  is  to  be 
critically  observed  and  facilitated  by  every  possible 
means.  The  object  is,  of  course,  to  produce  leather  in 
less  time  and  at  less  cost  than  heretofore. 

To  these  remarks  the  tanner  will  probably  reply  that 
he  has  neither  taste,  time,  nor  means  to  employ  in 
chemical  experiments.  But  if  this  is  so,  he  can  at  least 
join  with  his  brethren  and  endeavor  with  them  to  effect, 
by  concerted  action,  that  which  it  may  be  impossible  for 
a  single  individual  to  accomplish.  It  is  worth  while  to 
inquire  whether  our  associations  might  not  advanta¬ 
geously  employ  educated  chemists  to  unlock  for  them 
the  secrets  of  nature. 

There  is  no  denying  that  ignorance  is  the  real  bar  to 
our  progress  ;  that  our  pathway  to  success  winds  up  the 
hill  of  science.  If  we  cannot  travel  it  alone,  we  should 
secure  guides,  and  accept  whatever  assistance  is  at  hand. 

Leather  is  employed  for  many  useful  and  ornamental 
purposes,  and  numerous  are  its  applications  to  various 
branches  of  industry.  Besides  its  extensive  use  for 
covering  for  the  head  and  feet,  wearing  apparel,  saddles, 
harness,  etc.,  it  is  largely  employed  for  the  embellish¬ 
ment  of  objects  of  taste  and  ornament. 

Independently  of  the  direct  importance  of  the  leather 
trade,  it  exerts  a  very  decided  incidental  influence  in 
developing  the  resources  of  a  country,  by  giving  value 
to  certain  materials  used  in,  and  resulting  from,  the 
manufacture.  Besides  the  immense  quantity  of  bark 
which  it  consumes,  it  furnishes  the  raw  material  which 
gives  employment  to  thousands  of  artisans.  Even  the 
waste  material  of  slaughter-houses,  tanneries,  curriers’ 


20 


INTRODUCTION. 


shops  have  important  applications ;  the  horns  serving  for 
the  manufacture  of  combs,  buttons,  and  umbrella  furni¬ 
ture  ;  the  hairs  for  plasterers’  use,  the  spent  lime  for  the 
farmer,  the  skin  clippings  for  the  glue  boiler,  etc.  etc. 

Below  will  be  found  an  abstract  from  the  Preliminary 
Report  of  the  Eighth  Census,  showing  the  amount  of 
leather  produced  for  the  years  1850  and  1860  respec¬ 
tively,  also  the  quantities  furnished  by  each  State  during 
the  same  period.  The  tanners  of  the  United  States 
produced  in  1850,  exclusive  of  morocco  and  patent 
leather,  goods  to  the  value  of  $37,702,333,  and  in  1860 
the  product  reached  $63,090,751,  being  $25,388,418 
greater  than  during  the  corresponding  period  of  1850. 
The  largest  producers  of  leather  are,  in  their  order, 
New  York,  Pennsylvania,  and  Massachusetts.  The  for¬ 
mer  turning  goods  to  the  value  of  $20,758,017,  the 
second,  $12,491,631,  and  the  last,  $10,354,056,  being  an 
increase  in  the  three  States  of  $10,955,347  ;  $6,195,268 
and  $4,681,497  respectively  on  an  aggregate  increase  of 
$21,832,112. 

We  can  have  no  better  evidence  of  the  immense 
benefits  of  the  leather  trade  to  the  commerce  of  the 
entire  country  than  is  manifested  by  the  growth  and 
increase  of  this  single  article  of  production,  as  set  forth 
in  the  following  table,  during  the  ten  years  ending  June 
1,  1860,  and  the  exhibit  of  1850. 


States  and  Value  of  product 

Value  of  product 

Per  cent. 

Territories. 

in  1850. 

in  I860. 

increase. 

Maine 

$1,101,299 

$2,011,034 

18.2 

New  Hampshire 

944,554 

1,933,949 

104.1 

Vermont 

640,665 

1,000,153 

56.1 

Massachusetts 

5,612,559 

10,354,556 

82.3 

Rhode  Island 

133,050 

80,891 

Decrease 

Connecticut 

115,325 

953,182 

23.0 

Total  N.  E.  States. 

9,861,452 

16,333,811 

66.6 

New  York 

9,802,610 

20,158,011 

111.1 

Pennsylvania 

6,296,363 

12,491,631 

98.4 

New  Jersey 

1,269,282 

1,291,621 

2.1 

Delaware 

213,142 

31,240 

Decrease 

Maryland 

1,426,134 

1,123,033 

11.2 

Dist.  of  Columbia  56,000 

31,000 

Decrease 

Total  Mid.  States. 

19,065,491 

36,344,548 

90.1 

INTRODUCTION. 


21 


States  and 

Value  of  product 

Value  of  product 

Per  cent. 

Territories. 

in  1850. 

in  1S60. 

increase. 

Ohio 

$2,110,932 

$2,799,239 

32.6 

Indiana  . 

750,801 

800,387 

6.6 

Michigan 

401,730 

574,172 

42.4 

Illinois  . 

337,384 

150,000 

Decrease 

Wisconsin 

181,010 

498,268 

175.2 

Minnesota 

11,400 

Iowa 

24,550 

81,760 

23.3 

Missouri 

366,361 

368,826 

.6 

Kentucky 

1,108,533 

701,555 

Decrease 

Kansas  . 

850 

Total  W.  States 

5,281,351 

5,986,457 

13.3 

Utah 

93,255 

California 

223,214 

Oregon  . 

14,500 

Washington  . 

17,500 

Total  P.  States 

351,469 

Virginia 

927,877 

1,218,700 

31.3 

N.  Carolina  . 

363,647 

313,020 

Decrease 

S.  Carolina  . 

282,399 

150,985 

Decrease 

Georgia 

403,439 

393,164 

Decrease 

Alabama 

344,445 

340,400 

Decrease 

Louisiana 

78,085 

47,000 

Decrease 

Texas 

52.600 

123,050 

132.0 

Mississippi 

241,632 

223,862 

Decrease 

Arkansas 

78,824 

115,375 

46.3 

Tennessee 

804,631 

1,118,850 

38.9 

Total  S.  States 

3,777,579 

4,064,407 

13.8 

Aggregate  in  U.  S.  31,791,818 

63,090,751 

66.9 

The  production  of  leather  is  a  leading  industry  of 
much  importance  to  the  agriculturist  and  stock  raiser, 
as  well  as  to  the  commercial  interests,  inasmuch  as  it 
consumes  all  the  material  supplied  by  the  former,  and 
feeds  an  active  branch  of  our  foreign  import  trade.  In¬ 
cluding  morocco  and  patent  leather,  the  aggregate  value 
produced  in  the  Union  in  1860  exceeded  sixty-seven 
millions  of  dollars. 

If  we  add  to  the  sum  total  of  this  manufacture  the 
aggregate  value  of  all  the  allied  branches  into  which  it 
enters  as  a  raw  material,  or  take  an  account  of  the  capi¬ 
tal,  the  number  of  hands,  and  the  cost  of  labor  and 
material  employed  in  the  creation  and  distribution  of 


22 


INTRODUCTION. 


its  ultimate  products,  it  is  doubtful 'if  any  other  depart¬ 
ment  of  industry  is  entitled  to  precedence  over  that  of 
leather.* 

The  principal  steps  in  the  manufacture  of  leather 
are — 

1st.  The  washing  and  soaking  for  the  purpose  of  cleans¬ 
ing  and  softening  the  skins  and  preparing  them  for — 

2d.  The  d epilation  or  removal  of  the  hair.  This  is 
effected  by  the  use  of  lime,  or  other  substances,  which 
destroy,  dissolve,  and  soften  the  bulbous  roots  of  the  hair, 
and  thus  facilitate  their  removal  by  mere  mechanical 
scraping  with  a  blunt-edged  knife.  During  this  part  of 
the  process  another  important  end  is  generally  accom¬ 
plished  in  the  swelling  of  the  tissues,  and  their  prepara¬ 
tion  for  the  more  complete  and  easy  absorption  of  the 
tanning  principle.  The  primitive  mode  of  removing  the 
hair  was  that  of  shaving  it  off  with  a  knife,  but  the  use 
of  lime  for  this  purpose  was  known  even  among  the 
early  Egyptians.  When  the  rationale  of  the  depilation 
is  better  understood  by  practical  tanners,  the  slow  and 
inconvenient  process  of  depilation  by  means  of  lime  will 
probably  give  place  to  more  effective,  rapid,  and  econo¬ 
mical  methods,  such  as  the  use  of  the  hydrosulphuret  of 
calcium. 

3d.  Tanning.  This  step  consists  in  promoting  the 
combination  of  the  gelatinous  tissue  with  tannin  by  im¬ 
mersing  the  softened  and  unhaired  skins  in  an  infusion 
of  oak  bark,  or  other  substances  containing  tannin.  The 
tanning  influence  is,  probably,  not  exerted  solely  by  the 
tannin,  but  also  partly  by  the  extractive  matter,  more  or 
less  of  which  always  exists  in  tanning  material.  Dur¬ 
ing  the  soaking  the  epidermis  of  the  skin  disappears, 
and  the  tissue  of  the  latter  is  gelatinized,  and  thus  pre¬ 
disposed  to  chemical  union  with  the  tannin.  This 
gelatinization  of  the  tissue  is  all-essential,  and  is  pro¬ 
moted  doubtless  by  the  gallic  acid  fermentation  of  the 
tanning  material.  This  is  the  more  probable,  since  the 
same  effect  may  be  produced  by  the  use  of  very  dilute 

*  Preliminary  Report  on  the  Eighth  Census,  1S60,  by  Jos.  C.  G. 
Kennedy,  superintendent. 


INTRODUCTION. 


23 


acetic  and  sulphuric  acids,  and  since  gallic  acid  has  no 
primary  or  direct  influence  on  the  tanning.  Since  ex¬ 
posure  to  moisture,  to  air,  and  a  temperature  of  77°  to 
S6°  are  the  requisites  for  this  fermentation,  which  is 
developed  by  the  action  upon  tannin  of  a  ferment  which 
is  always  present  in  tanning  material,  converting  it  into 
gallic  acid.  In  consequence  of  this  change,  the  pro¬ 
longed  exposure  of  the  liquor  diminishes  its  tanning 
power. 

4th.  Drying,  rolling,  and  other  operations  intended  to 
perfect  the  quality  and  appearance  of  the  leather. 

ORIGIN  AND  DEVELOPMENT  OF  THE  ART  OF 
TANNING.* 

Upon  the  conviction  that  it  will  he  agreeable  to  all 
in  the  trade  to  possess  authentic  data  of  an  art  the 
practice  of  which  is  their  vocation,  and  to  follow  its 
gradual  development  ab  initio ,  we  beg  leave  to  present 
our  readers  with  the  following  faithful  sketch  of  the 
gradual  rise  and  progress  of  the  art  of  tanning,  and  we 
shall  take  pains  to  carefully  collect  all  other  notices  on 
this  subject  of  interest  and  value  to  the  craft,  and  as  a 
retrospect  of  its  history. 

The  origin  of  the  tanner’s  art  is  lost  in  antiquity ;  but 
it  is  supposed  to  have  been  an  oriental  invention ;  at 
least  it  was  earlier  brought  to  a  state  of  perfection  in  the 
East  than  in  Europe. 

According  to  Chinese  authors,  it  was  their  ruler,  Schin- 
fcing,  who  taught  them  to  prepare  the  skins  of  animals, 
and  to  remove  the  hairs  with  wooden  rulers.  Pliny 
ascribes  the  invention  of  tanning  to  Tychius  of  Bosotia  ; 
but  this  is  also  uncertain.  At  that  time  those  who  first 
introduced  anything  into  a  country  generally  received 
the  credit  of  having  invented  it.  The  use  of  the  skins 
of  animals  for  clothing  was  known  in  the  remotest  ages, 
and  but  moderate  attention  and  inventive  power  are 
requisite  to  conceive  and  follow  out  the  idea  of  their 
employment  in  this  manner. 

\ 

*  From  the  “Gerber  Courier,”  Vienna,  Austria. 


24 


INTRODUCTION. 


The  inconvenience  of  raw  hides,  and  their  roughness 
and  hardness  preventing  their  adaptation  to  the  body, 
awoke  reflection  ;  men  thought  to  discover  the  causes  of 
these  defects,  as  well  as  the  means  of  remedying  them, 
and  thus  arose  with  a  gradual  progress  towards  perfection 
the  art  of  converting  the  raw  hide  into  leather  and  for 
clothing,  which  mode  of  preparation  is  now  called  Tan¬ 
ning. 

The  more  nations  increased  in  number  the  greater 
became  the  demand  for  the  necessity  of  civilization  and 
luxury,  and  thus  forced  and  attracted  by  necessity  and 
gain,  many  experiments  were  made  with  a  view  to  the 
improvement  of  tanning,  until  those  excellent  inventions 
were  attained  which  have  brought  tanning  to  its  present 
state  of  perfection.  In  these  experiments  the  principal 
properties  of  tanned  leather  were  not  lost  sight  of.  At¬ 
tention  was  paid  to  the  preparation  of  the  hide  so  as  to 
render  it  pliant  and  more  impervious  to  moisture. 

New  inventions  and  discoveries  are  still  making 
every  day  by  workmen  and  scientific  men ;  often  acci¬ 
dentally,  but  often  by  study  and  reflection ;  and  who 
knows  but  that  in  a  few  years  tanning  will  be  brought  to 
a  much  higher  point  of  perfection  than  it  has  hitherto 
attained.  Chemistry,  the  fundamental  science  of  tan¬ 
ning,  has  made  astonishing  progress  in  the  last  few  years, 
and  ought  this  not  also  to  be  the  case  in  the  tanning 
art,  especially  as  it  is  based  upon  chemical  principles  I 

The  oldest  method  of  tanning  is  red  or  bark  tanning, 
or  that  in  which,  in  addition  to  the  wooden  and  iron 
scraping  and  rubbing  instrument  used  in  the  preparation 
or  improvement  of  the  hide  or  skin,  lime-water,  and 
astringent  extracts  from  oak  and  other  kinds  of  bark, 
or  from  other  vegetable  substances,  are  employed.  It  is 
called  red  tanning  because  the  tanning  substances  always 
contain  more  or  less  coloring  matter,  which  dye  the 
leather  through  and  through  of  a  more  or  less  reddish 
color. 

The  ancient  orientals  understood  the  art  of  preparing 
not  only  common  leather,  but  even  good,  and  often  finely 
colored  varieties,  similar  to  our  Morocco  and  Cordovan. 


INTRODUCTION. 


25 


Persian  and  Babylonian  leather  lias  been  celebrated  time 
out  of  mind.  Many  centuries  back,  such  leather  -fras 
brought  from  Asia  into  Europe,  first  into  Turkey,  Prussia, 
and  Hungary,  and  thence  later  to  Germany,  Holland, 
England,  France,  Spain,  etc.,  and  these  countries  learned 
subsequently  to  manufacture  leather  themselves.  In 
the  first  centuries  of  Christianity,  the  Turks,  Russians, 
and  Hungarians  were  the  most  celebrated  tanners  ;  sub¬ 
sequently  England,  the  Netherlands,  and  Spain  endea¬ 
vored  to  equal  them. 

Among  fine  sorts  of  leather  of  foreign  origin,  Cordovan, 
Morocco ,  Shagrin,  and  Russia  leather  have  at  all  times 
been  especially  famous.  Cordovan,  a  soft,  small-grained, 
colored  leather,  had  already  been  prepared  by  the  ancient 
orientals.  Its  name  is  derived  from  the  Spanish  city  of" 
Cordova,  where  it  was  probably  first  introduced  into 
Europe,  and  where,  for  a  long  time  afterwards,  it  was 
chiefly  manufactured.  It  enjoyed  a  great  reputation  in 
the  eleventh  century,  when  the  most  distinguished  per¬ 
sons  wore  shoes  of  Cordovan  leather.  The  French  name 
for  shoemaker,  “  Cordonnier ,”  appears  also  to  be  derived 
from  this  leather.  The  best  qualities  are  now  made  in 
Constantinople,  Smyrna,  and  Aleppo.  The  best  known 
German  Cordovan  is  the  Bremen  variety. 

From  the  gradual  improvement  of  Cordovan  sprang 
Morocco,  called  also  Turkish  and  Spanish  leather,  a  still 
handsomer  leather  than  Cordovan.  This  beautifully 
colored  and  brilliant  leather  has  always  been  most  ex¬ 
cellently  manufactured  in  Morocco,  in  the  Levant,  in 
Asiatic  and  European  Turkey,  in  Krim  Tartary,  in 
Aleppo  and  Smyrna,  and  in  the  Island  of  Cyprus,  and 
very  well  also  in  Russia,  Poland,  Hungary,  and  Spain, 
but  especially  in  England,  France,  Holland,  Switzerland, 
and  Germany  (in  the  latter  country  at  Offenbach  on  the 
Main,  and  Calin,  in  Wurtemburg). 

Shagrin  (in  Turkish,  Sagri,  and  Persian,  Sagre )  is 
chiefly  celebrated  for  its  hardness  and  strength,  and  for 
the  peculiarity  of  the  grain  side,  which  appears  as  if 
covered  with  globular  granules ;  it  is  also  of  eastern 
origin.  The  best  Shagrin  is  now  made  in  Persia,  Con- 


26 


INTRODUCTION. 


stantinople,  Algiers,  and  Tripoli.  The  production  of  the 
smfdl  globular  granules  on  the  grain  side  was  for  a  long 
time  kept  secret.  We  were  first  informed  years  since 
by  the  celebrated  traveller,  Pallas,  that  they  were  pro¬ 
duced  by  stamping  the  hard  seeds  of  the  wild  orach  (Che- 
nopodium  album)  into  the  hide,  spread  on  the  ground ; 
the  seeds  were  afterwards  knocked  out  and  the  hide 
scraped  on  the  indented  side,  and  soaked  in  water  for 
two  days.  There  is  another  description  of  shagrin 
totally  different,  made  from  fish-skin,  called  fish-skin 
shagrin ;  it  is  used  for  covers,  wood  polishing,  etc. 

Russia  leather  is  a  strong  and  pliant  leather,  generally 
red  or  black,  with  a  peculiarly  penetrating  odor,  and  was 
undoubtedly  invented  by  the  ancient  Bulgarians.  It  is 
'only  lately  that  we  have  learned  the  mode  of  preparing 
this  leather.  Among  other  things,  we  first  perceived 
that  the  peculiar  odor  arose  from  the  birch  oil  which 
was  rubbed  into  the  leather.  Inuften ,  the  German  name 
of  this  leather,  is  derived  from  the  Bulgarian  word 
“  Jufti ,”  a  pair,  as  the  Bulgarians,  when  they  colored 
hides,  always  sewed  them  together  by  pairs  in  the  form 
of  a  bag,  with  the  grain  side  inwards;  the  coloring  liquor 
was  then  poured  in  and  the  hides  kept  in  motion.  The 
best  Russian  leather  is  made  in  various  Russian  and 
Lithuanian  provinces. 

By  tanning  (i.  e.,  white  tanning),  which  appears  to 
have  been  invented  in  Hungary  before  the  twelfth  cen¬ 
tury,  a  white  pliant  leather  is  obtained  by  tanning  with 
alum  instead  of  bark.  This  leather  is  used  principally 
by  glovers  and  harness-makers.  In  Hungary,  also,  not 
long  after  the  invention  of  tanning,  chamois  dressing 
was  invented.  In  this  method  neither  bark  nor  alum 
is  employed ;  the  leather  is  simply  dressed  by  rolling 
and  other  powerful  operations,  first  with  bran  and  sub¬ 
sequently  with  animal  fat  (train  oil).  In  order  that  the 
fat  may  the  better  penetrate  through  and  through,  the 
grain  side  is  cut  away  with  sharp  instruments.  For 
this  reason  chamois  leather  is  rough  or  velvety  on  both 
sides.  Lately  gloves  and  breeches  are  made  from  this 
kind  of  leather,  the  latter  principally  from  white  tanned 


INTRODUCTION. 


27 


buckskin.  The  Hungarians  were,  in  ancient  times, 
especially  celebrated  for  their  white  tanned  leather, 
which  was  imitated  in  France  as  long  ago  as  three  hun¬ 
dred  years.  In  chamois  leather,  the  most  famous  is  the 
fine,  white,  shining  French  and  Dane’s  leather  (made 
.from  lamb  and  goat  skins),  from  which,  by  means  of  a 
peculiar  varnish,  the  so-called  kid  gloves  are  made. 

A  profession  continues  progressive,  and  cannot  reach 
its  highest  point  until  its  limit  can  be  precisely  defined. 
An  excellent  means  by  which  to  improve  a  profession 
consists  in  pointing  out  the  goal  and  end  to  be  attained, 
and  the  bounds  within  which  it  must  be  confined.  With¬ 
out  this  precaution,  we  exhaust  ourselves  in  single  and 
unconnected  researches,  without  reference  to  each  other, 
and  the  knowledge  which  we  acquire  is  dissipated  and 
loses  in  force  as  it  recedes  from  the  common  focus. 

A  small  number  of  principles  and  a  great  mass  of  con¬ 
clusions  ;  this  is  the  history  of  all  arts,  all  sciences. 
The  principles  must  rest  upon  reliable  facts  derived  from 
experience  and  observation;  but  an  author  cannot  render 
all  conclusions  and  explanations.  The  principles  are 
not  numerous  and  are  easy  of  comprehension,  but  the 
conclusions  arising  from  them  are  innumerable,  and 
lucidity  is  only  to  be  arrived  at  by  placing  them  in  order 
under  the  general  laws  to  which  they  respectively  belong, 
and,  therefore,  a  judicious  classification  is  requisite. 

Tanning,  in  general,  is  divided  into  various  branches, 
although  all  may  be  practised  together  by  the  same  tan¬ 
ner.  We  will  first  give  nearer  data  upon  the  origin  and 
development  of  our  system  of  tanning,  and  subsequently 
consider  minutely  and  singly  every  process  and  the 
different  methods  and  systems  in  our  tanneries  at  home 
and  abroad,  keeping  constantly  in  view  the  statistics  of 
the  foreign  leather  trade  and  manufactures  as  compared 
with  our  own.  We  beg  our  readers  to  go  back  some 
centuries  in  history,  and  they  will  be  convinced  that 
the  products  of  our  trade  were  known  in  the  time  of 
Moses ;  for  at  that  period,  leather  carpets  were  already 
used  in  tents ;  these  we  may  still  meet  with  at  present 
among  the  Arabs.  Colored  leather  seems,  also,  to  have 


28 


INTRODUCTION. 


been  common,  for  Ezekiel  speaks  of  fine  red  leather, 
which  was  probably  our  splendid  red  morocco.  Leather 
was  also  used  in  the  remotest  ages  by  the  Israelites  as 
a  material  to  write  upon,  for  they  used  strips  made  of 
leather  for  this  purpose.  According  to  the  testimony  of 
Herodotus,  the  ancient  Ionians  wrote  their  annals  upon 
sheepskin,  and  the  ancient  Persians,  likewise,  according 
to  Diodorus  of  Sicily. 

According  to  the  accounts  of  Herodotus,  the  ancient 
Libyans  wore  leather  clothing ;  the  Ichthyopha gists  on 
the  banks  of  the  Araxes  dressed  themselves  in  seal¬ 
skins,  and  in  the  time  of  Alexander,  the  wild  inhabitants 
of  Geodrosia  used  the  hides  of  animals  for  clothing  and 
covered  their  dwellings  with  leather. 

Homer  praises  the  splendid  half  boots  of  Agamem¬ 
non,  and  Hesiod  recommends  leather  shoes  lined  with 
fur.  For  many  years  leather  was  used  by  the  Greeks 
in  the  construction  of  ships ;  especially  by  the  Phoeni¬ 
cians,  who  originally  inhabited  an  arid,  sandy  corner  of 
the  earth,  between  the  Bed  Sea  and  the  Mediterranean, 
where  the  soil  was  not  favorable  to  the  growth  of  tim¬ 
ber,  and  they  were  obliged  to  supply  its  place  by  cover¬ 
ing  their  boats,  constructed  of  willows  woven  together, 
with  leather  or  hides,  which  even  thus  early  were  sub¬ 
jected  to  a  certain  amount  of  dressing.  The  ancient 
Germans,  also,  who  lived  on  the  sea-coast,  and  the 
original  Britons,  equally  possessed  this  custom. 

It  is  asserted  that  the  art  of  dressing  leather  in  gen¬ 
eral  upon  the  so-called  Hungarian  method,  was  first 
brought  from  Senegal,  in  Africa,  and  made  known  to  us 
in  the  middle  of  the  sixteenth  century,  by  one  Buscher, 
the  son  of  a  tanner  in  Paris ;  at  that  time  leather  was 
common  in  Hungary,  and  that  dressed  there  was  very 
highly  esteemed.  In  the  year  1584,  two  German  tan¬ 
ners  named  Lasmagne  and  Aurand  came  to  Neuchatel 
in  Lorraine,  where  they  worked  at  their  trade ;  from 
thence  they  went  to  St.  Diziers,  in  Champagne,  and 
finally  to  Paris,  where  they  prepared  very  good  leather. 

The  theory  that  the  preparation  or  tanning  of  hides 
was  discovered  centuries  ago,  and  that  the  leather  pro- 


INTRODUCTION. 


29 


* 

duced  was  employed  for  the  same  purpose  as  at  present, 
is  further  confirmed  by  the  following  old  proverb,  which 
is  a  proof  that  leather  shoes  were  already  worn  at  that 
time,  viz:  “We  must  not  steal  leather  to  give  away  shoes 
in  God’s  named  This  refers  to  the  legend  of  St.  Cris¬ 
pin,  who  stole  leather  to  make  shoes  out  of  it  for  the 
poor.  In  the  old  form  of  speech,  “  To  draw  from  the 
leather ,”  signified  to  draw  the  sword.  In  low  Saxon 
the  same  expression  signifies  to  undress. 

Parchment  Dressing. — Parchment  was  known  long 
before  the  invention  of  paper ;  for  sheep  and  goatskins 
were  used  to  write  upon  in  the  time  of  Herodotus,  48-4 
A.  C. ;  the  name  is  derived  from  the  City  of  Pergamus, 
in  Asia  Minor,  where  it  was  excellently  manufactured. 
The  best  parchment  is  prepared  from  calfskin,  and  in¬ 
ferior  qualities  from  sheep,  goat,  ass,  and  pig  skins. 
The  fine  virgin  parchment  is  made  from  the  skins  of 
new-born  lambs. 

Artificial  parchment,  which  was  discovered  in  Eng¬ 
land,  consists  of  linen,  cloth,  or  paper,  which  is  tightly 
stretched,  and  then  a  paste  composed  of  gypsum,  white 
lead,  powdered  lime,  water,  and  parchment  glue,  is  laid 
on  with  a  brush  four  times :  it  is  then  smoothed  with 
pumice  stone,  and  lastly  steeped  in  a  bright  oil  varnish. 

The  use  of  parchment  is  not  very  extensive ;  beyond 
the  ordinary  purposes  it  is  sometimes  used  for  printing, 
for  organ  bellows,  and  for  sieves,  and  in  England  for 
sounding  boards  in  stringed  musical  instruments.  In 
Germany  it  is  principally  manufactured  at  Bentheim 
and  Schuttorf  in  Hanover,  and  also  in  Augsburg,  Nu¬ 
remberg,  Breslau,  and  Dantzic.  Holland,  England,  and 
France  manufacture  excellent  parchment. 

Such  is  the  historical  origin  of  our  leather  trade. 
The  gradual  development  and  progress  of  technical  tan¬ 
ning  have  been  promoted  and  assisted  by  many,  and 
among  the  most  zealous  are  MacBride,  St.  Real ,  Proust , 
Hermstadt,  Vauguelin ,  Chaptal ,  Seguin ,  Desmond ,  Von 
Meidinger,  Aikin,  and  others.  Attempts  have  been 
made  to  discover  new  methods  by  which  hides  and  skins 
could  be  better  tanned,  and  in  a  shorter  space  of  time, 


30 


INTRODUCTION. 


than  by  the  usual  mode  of  treatment.  In  the  year  1778 
MacBride  discovered  the  process  of  raising  with  diluted 
sulphuric  acid  (1  part  acid  to  400  parts  water). 

Later  great  attention  was  attracted  to  the  system  of 
quick  tanning,  discovered  in  1795  by  Seguin,  by  which 
hides  and  skins  were  tanned  in  much  less  time  than 
formerly.  This  new  process  was  tested  by  experts,  and 
found  to  be  partially  good  and  partially  deficient.  In 
1801,  Banks  discovered  the  tanning  property  of  Terra 
Japonica  (Catechu).  Since  that  time  tannin  has  been 
discovered  in  a  great  number  of  plants. 

The  English  discovered,  in  the  last  century,  the  art 
of  varnishing  leather,  which  was  soon  after  imitated  in 
Germany  with  complete  success. 

Ballamy,  Yon  Hildebrandt,  Edward,  and  others  in¬ 
troduced  the  art  of  preparing  water-proof  leather. 

Whatever  may  be  facts,  it  is  to  be  presumed  that  the 
most  ignorant  races  of  antiquity,  whose  chief  occupa¬ 
tion  was  the  chase,  possessed  the  knowledge  of  giving 
a  certain  preparation  to  the  raw  animal  hides  to  protect 
them  from  decay,  and  to  render  their  necessary  clothing 
convenient ;  they  were  certainly  driven  to  invention  by 
necesssity,  and  thus  the  invention  of  the  art  of  tanning 
was  probably  the  work  of  accident,  like  the  invention 
of  most  of  the  other  arts.  To  them,  consequently, 
must  the  invention  of  the  art  of  tanning  leather  be 
ascribed,  although  it  must  be  conceded  that  this  art 
owes  its  proper  cultivation  and  perfection  to  more  re¬ 
cent  ages. 


PART  I. 

CHEMISTRY  OF  TANNING. 


SECTION  I. 

TAN  AND  TANNIN. 

The  second  principal  component  of  leather,  such  as 
that  manufactured  into  boots,  shoes,  &c.,  is  Tannin ,  or 
tannic  acid ,  a  substance  of  vegetable  origin  and  very  ex¬ 
tensively  disseminated  in  plants  and  trees.  For  a  long 
time  the  agents  which  gave  such  virtues  to  oak  bark, 
in  converting  prepared  skins  into  leather,  were  little 
known,  and,  consequently,  the  peculiar  relation  of  the 
proximate  principle  of  this  article  could  not  be  under¬ 
stood,  notwithstanding  that,  in  the  absence  of  this 
knowledge,  the  leather  manufactured  was  sometimes  of 
prime  quality.  Dr.  Lewis  was  the  first  who  drew  the 
attention  scientifically  to  the  subject.  He  observed, 
during  an  investigation  of  the  nutgalls,  that  they  con¬ 
tained  a  substance  which  gave  a  black  compound  with 
a  sesqui-salt  'of  iron  and  precipitated  isinglass.  Dey- 
eusee,  who  also  studied  the  subject,  noticed  this  sub¬ 
stance,  but  considered  it  a  peculiar  resinous  matter.  It 
w7as  not,  however,  till  Seguin  published  the  results  of 
his  labors,  that  any  definite  account  of  it  was  given. 
This  chemist  shovted  that  the  unknown  body  differed 
from  the  acid  of  galls — gallic  acid  ;  that  it  combined 
with  animal  matters,  more  particularly  albumen  and 
gelatin,  and  formed  with  them  unalterable  bodies,  the 
analogue  of  which  constituted  the  main  bulk  of  leather. 
Since  then,  manufacturers  have  given  great  attention  to 
this  principle  in  the  tanning  material,  and  the  conse- 


32 


CHEMISTRY  OF  TANNING. 


quences  are  that  a  greater  variety  of  substances  pro¬ 
ducing  tannin,  or  desirable  for  making  leather,  have 
been  discovered,  and  that  considerable  expedition  in  the 
process  has  been  attained.  Although  the  before-men¬ 
tioned  chemists,  with  Davy,  Chevreul,  Pelletier,  La¬ 
grange,  Guillot,  Hatchett,  Tromsdorff,  Hichter,  and 
Proust,  may  be  justly  said  to  have  given  a  scientific 
exposition  of  tannic  acid  and  its  behavior,  and  likewise 
pointed  out  its  quantity  in  those  plants  that  yield  it  most 
abundantly,  still  several  more  recent  investigations  have 
contributed  to  the  stock  of  information  on  this  subject. 
According  to  W aemstlenberg,  tannin  exists  only  in  peren¬ 
nial  plants,  and  almost  solely  in  the  permanent  parts. 
For  example: — 

1.  In  the  perennial  roots  of  certain  annual  plants,  as 
the  Septfoil  and  Bistort  or  snakeweed. 

2.  In  the  bark  of  the  trunks  and  roots  of  nearly  all 
perennial  trees,  especially  in  the  true  cortical  portion. 

3.  In  the  trunk  and  sap  of  many  trees. 

4.  In  the  leaves  of  perennial  plants. 

5.  In  the  leaves  of  different  varieties  of  oak,  of  the 
Rhus  coriara  (Sumac),  of  the  Arbutus  uva  ursi  (Bear- 
berry),  of  the  Arbutus  unedo  (Strawberry),  etc.,  in 
large  proportion. 

6.  In  the  capsule  of  the  unripe  fruit  of  the  Quercus 
sober  cegilops  (Yalonia  oak),  Juglans  regia  (Walnut); 
JEsculus  hippocastanus  (Horse-chestnut). 

7.  In  the  pulp  of  the  fruit  of  the  Punica  granatum 
(Pomegranate)  ;  Rosa  pimpinelli  folia  ;  Garcinia  man- 
gostana  (Mangosteen),  and  in  different  species  of  Anona. 

The  following  table  exhibits  the  names  of  the  prin¬ 
cipal  materials  used  by  tanners. 


Common  Name. 

Botanical  Name. 

Growth. 

Oak 

Bark 

Quercus  pedunculata 

Every  country. 

Larch 

U 

Pinus  larise 

Scotland. 

Mimosa 

a 

Acacia  sp. 

New  South  Wales. 

Babodl 

ll 

Acacia  arabica 

Bengal. 

Cork  Tree 

u 

Quercus  suber 

Laruch,  Rabat,  etc. 

Hemlock 

it 

Abies  canadensis 

United  States. 

Sumach 

It 

Ph  us  coriaria 

Sicily. 

Valonia 

Quercus  segilops 

Smyrna,  Trieste,  etc. 

TAN  AND  TANNIN. 


33 


Common  Name. 
Divi-Divi 


Botanical  Name. 
Csesalpinia  coriarici 


Growth. 


Maracaibo,  Rio  de  la 


Myrobalans 
Algarobilla 
Terra  Japonica 
Cctch 
Kassu 


Areca  catechu 


Terminalia  sp. 
Prosopis  pallida 
Acacia  catechu 


i  l 


Hacha,  Savauilla. 
Bengal. 

Valparaiso. 

East  Indies. 
Calcutta,  Singapore. 
Ceylon. 


Besides  the  foregoing,  which  are  partly  well  known 
in  the  trade,  other  astringent  substances  have  been 
brought  before  the  public  to  be  employed  per  se  as  tan¬ 
ning  materials,  or  with  oak  bark  as  an  adjunct.  These 
are  various  extracts  from  species  of  the  acacia  tribe ; 
Gambir,  the  extract  of  the  Nauclea  gambir ,  from  Singa¬ 
pore;  Maiyrove  bark  ( Rhizopora  mangle ),  from  Arra- 
cance ;  Turwar  or  Cassia  bark;  Avaraputtai  ( Cassia 
auriculata ),  from  Vazigapatam  ;  Saracondraputtai  (Cas¬ 
sia  fistula ),  from  Madeira ;  Saul  tree  bark,  from  the 
Saul  Forests ;  Pomegranate  rind ;  Darunka  pucke 
( Dahima  jegota),  from  Kemaon  ;  Dalumka  Kiiola,  from 
Calcutta;  Jamoon  bark  ( Eugenia  jambolana );  Pearl 
bark,  from  C'uttah  ;  Samah  bark,  from  Singapore  ;  Van- 
gay  or  Gum  kino  (  Pterocarpus  dalbergoides ),  from  Mala¬ 
bar  ;  Kino  extract  of  the  Buchanania  patifolia ,  etc.  etc. 

We  must  note  here — 

1.  That  tannin  is  never  found  to  any  extent  in  the 
interior  of  the  trunks  of  trees. 

2.  That  it  does  not  exist  in  poisonous  plants,  nor  in 
those  with  a  milky  or  viscid  sap. 

3.  That  its  proportion  is  greater  in  old  than  in  young 
plants. 

4.  That  the  tannin  is  converted  into  bitter  principle, 
as  the  plant  increases  in  age. 

5.  That  it  is  most  abundant  in  the  cortical  layers  of 
the  bark,  and  is  usually  absent  altogether  in  the  epi¬ 
dermis. 

6.  That  the  proportion  of  tannin  in  bark  varies  with 
the  season,  decreasing  as  the  severity  of  the  winter  in¬ 
creases. 

7.  That  the  true  extreme  in  quantities  are  allowed  in 
winter  and  spring. 


3 


34 


CHEMISTRY  OF  TANNING. 


CHAPTER  I. 

PURE  TANNIN. 

CHEMICAL  PROPERTIES  OF  PORE  TANNIN — COMPOSITION — PREPARATION 

Chemical  Properties. 

By  examining  any  of  the  numerous  substances  unia- 
tioned  above,  it  will  be  found  that  they  yield  a  product 
which  is  capable  of  precipitating  a  solution  of  gelatin, 
and  also  of  giving  a  greenish  or  bluish-black  one,  with 
solutions  of  sesqui-salts  of  iron.  To  matter  exhibiting 
this  reaction,  and  having  an  astringent  taste,  the  name 
of  Tannin  was  given,  irrespective  of  whatever  difference 
might  be  exhibited  upon  further  comparison.  Now 
many  of  those  bodies  which,  in  common  with  the  true 
type  of  tannin  (that  which  is  extracted  from  galls),  pre¬ 
cipitate  gelatin,  and  so  far  show  that  they  are  eligible 
for  tanning  materials,  are  known  to  differ  in  that  charac¬ 
teristic  ;  for  instance,  some  possess  acid  properties,  whilst 
others  are  devoid  of  them ;  and  although  towards  gela¬ 
tin,  their  reactions  are  similar,  their  atomic  constitu¬ 
tion  is  widely  different.  Regarding  their  effect  in  con¬ 
verting  skin  into  leather,  this  dissimilarity  is  not  very 
material,  as,  when  the  components  of  each  one  are  com¬ 
pared,  a  distinction  is  also  made  with  respect  to  the 
physical  appearance  of  the  precipitate  they  afford  with 
a  sesqui-salt  of  iron,  and  by  this  all  the  known  tanning 
materials  are  divided  into  two  classes.  In  the  first  of 
these  are  placed  gall-nuts,  and  the  barks  of  the  several 
oaks,  and  the  second  include  the  quinquina,  the  cachou, 
kino,  pine  barks,  etc.  The  tannin  afforded  by  the  first 
throws  down  a  bluish-black  or  purple  combination, 
whilst  the  precipitate  afforded  by  the  second  is  greenish. 
Experiments  have  shown  that  such  distinctions  are  not 
very  marked,  since  the  tannic  acid  from  nutgalls  or  oak 
bark,  in  the  presence  of  an  alkali,  will  occasion  a  green¬ 
ish  precipitate  when  added  to  a  sesqui-salt  of  iron,  and 
a  bluish  or  violet  compound  when  acids  are  present. 


PURE  TANNIN. 


35 


Hatchett  first  observed  that  many  plants  contain  a 
carbonaceous  principle,  which,  when  acted  upon  by  ni¬ 
tric  or  sulphuric  acids,  according  to  the  method  of  Chev- 
reul,  yield  a  substance  which,  like  the  tannin  of  the 
foregoing  barks  and  fruits,  throws  down  gelatin,  and 
renders  it  imputrescible.  This  variety  has  been  desig¬ 
nated  artificial  tannin  ;  but  in  the  present  state  of  chem¬ 
ical  science,  it  could  not  be  compounded  with  the  natu¬ 
ral  products.  Berzelius,  Geiger,  W altl,  and  C avallius 
are  of  opinion  that  tannin,  from  whatever  source  it  may 
be  obtained,  is  identical,  and  that  the  difference  of  the 
reaction  with  the  iron  salt  must  be  attributed  to  impuri¬ 
ties  which  are  accidentally  present.  Stenhouse,  in  his 
more  recent  researches,  has  shown  that  such  is  not  the 
case,  but  that  all  those  forming  precipitate  with  sesqui- 
oxide  of  iron,  varying  from  the  color  of  that  which  the 
tannin  of  nutgalls  affords,  must  be  regarded  as  a  distinct 
substance,  in  which  case  there  seems  to  be  an  almost  end¬ 
less  variety.  Even  when  the  iron  reactions  of  some  tan¬ 
nins  agree,  and  also  appear  analogous  in  other  chemical 
relations,  the  same  chemist  states  that  the  composition 
is  frequently  diverse. 

In  its  purity  tannic  acid  is  colorless,  inodorous,  pos¬ 
sesses  a  highly  astringent  taste,  and  is  very  soluble  in 
water.  It  is,  however,  devoid  of  all  bitterness,  notwith¬ 
standing  its  astringency  is  so  powerful.  On  testing  the 
aqueous  solution  with  litmus,  the  reaction  evidences  the 
acid  nature  of  the  tannin ;  and  further,  by  treatment 
with  an  alkaline  carbonate,  carbonic  acid  is  freely  dis¬ 
played,  showing  that  a  combination  of  the  alkaline  base 
and  the  tannin  has  taken  place.  With  the  oxides  of 
the  heavy  metals  it  in  a  great  measure  combines,  giving 
rise  to  precipitates  which  are  the  tannates  of  the 
respective  bases,  and  generally  possess  a  color  more  or 
less  remarkable.  Thus  an  infusion  of  nutgalls  reacts 
in  the  following  manner: — 


36 


CHEMISTRY  OF  TANNING. 


With  a  neutral  solution  of  salts  of 

Precipitates  given. 


Protoxide  of  Manganese, 

Brande. 
Dirty  yellow , 

Dumas. 

“  Iron, 

Purple  tint, 

— 

Sesquioxide  of  Iron, 

Black, 

Blue  black. 

Oxide  of  Zinc, 

Dirty  yellow, 

— 

“  Tin, 

Straw  “ 

Yellowish. 

Bioxide  “ 

Fawn  “ 

U 

Oxide  of  Cadmium, 

_ 

— 

Protochloride  of  Copper, 

Yelloiv  brown, 

Gray. 

i  l 

Protonitrate  “ 

Green, 

Oxide  of  Lead, 

Dingy  yellow, 

White. 

Teroxide  of  Antimony, 

Straw,  “ 

H 

“  Bismuth, 

Yellow, 

Orange. 

Oxide  of  Cobalt, 

— 

Yellowish-white. 

Salts  of  Cerium, 

_ 

Yellowish. 

“  Titanium, 

_ _ 

Blood  color. 

“  Tellurium, 

. — 

Isabelle  yellow. 

“  Chromium, 

_ 

Brown. 

“  Tantalum, 

— 

Orange. 

“  Molybdenum, 

_ 

Brown. 

“  TJranium, 

_ 

Brownish-red. 

“  Silver, 

- - 

Pale  yellow. 

“  Platinum, 

— 

Greenish  shade. 

“  Gold, 

— 

Brown. 

“  Osmium, 

— 

Bluish-purple. 

In  making  the  foregoing  experiments,  it  is  necessary 
to  employ  neutral  solutions  of  the  salts,  otherwise  any 
excess  of  the  acid  may  not  only  alter  the  shade  of  the 
precipitate,  but  prevent  it  altogether.  This  is  especially 
the  case  with  salts  of  iron  and  titanium.  When  a  solu¬ 
tion  of  tannic  acid  is  added  to  another  of  protosulphate 
of  iron,  according  to  Mr.  Dumas,  no  precipitate  occurs ; 
but  if  one  of  the  sesquisulphates  be  substituted  there  is 
an  abundant  deposit  of  a  blue-black  color. 

By  exposing  a  solution  of  tannic  acid  to  the  air,  at  a 
moderately  elevated  degree  of  heat,  oxygen  is  freely 
absorbed,  and  an  equal  volume  of  carbonic  acid  is  disen¬ 
gaged.  Upon  examination,  the  matter  in  solution  will 
be  found  to  be  wholly  transformed  into  two  other  sub¬ 
stances,  gallic  and  ellagic  acid,  the  former  of  which  is 
in  excess,  and  is  dissolved  in  the  liquid,  whilst  the 


PURE  TANNIN. 


37 


latter  remains  insoluble  in  the  form  of  a  yellowish 
powder. 

This  transformation  takes  place  in  the  aqueous  ex¬ 
tract  of  gall-nuts,  much  more  readily  than  in  one  of 
pure  tannin  ;  this  is  particularly  the  case  if  the  marc  or 
insoluble  residue  of  the  galls  be  left  in  contact  with  the 
liquid,  as  it  induces  a  fermentive  action,  which  brings 
about  the  transformation  the  more  readily.  When 
boiled  with  hydrochloric  or  sulpliuric  acids,  gallic  acid 
is  also  formed,  together  with  grape  sugar,  which,  as 
Strecker  states,  remains  in  the  mother  liquid  after  the 
newly-formed  acid  is  removed  by  crystallization.  The 
change  here  induced  may  be  represented  thus: — 

C51H32034  +  10HO  =  3(C14H3073H0)  +  C12H120122Aq. 

Gallo-tannic  acid.  Water.  Gallic  acid.  Cellulose. 

A  concentrated  solution  of  caustic  potash  at  the  boil¬ 
ing  point,  has  also  the  effect  of  transforming  tannic  into 
gallic  acid ;  and  if  air  or  oxygen  be  admitted,  of  con¬ 
verting  the  latter  into  an  ulmin-like  substance.  Hydro¬ 
chloric,  nitric,  phosphoric,  and  arsenic  acids  occasion  in 
strong  solution  of  tannic  acid  white  precipitates  which 
are,  as  stated  by  Berzelius ,  compounds  of  the  tannin 
with  those  acids ;  all  these  precipitates  are,  however, 
readily  decomposed,  and  their  tannin  changed  into  gallic 
acid,  beseizing  them  with  dilute  sulphuric  acid,  or  with 
an  excess  of  alkali.  If  a  cold  aqueous  solution  of  tan¬ 
nin  be  mixed  with  another  of  gelatin,  isinglass,  bone- 
size  or  glue  in  excess,  an  opaque  white  precipitate  is 
obtained  of  tanno-gelatin,  that  is  soluble  in  the  super¬ 
natant  fluid. by  the  help  of  heat.  When,  however,  the 
conditions  are  reversed,  and  an  excess  of  tannin  is  taken, 
it  happens  that,  instead  of  dissolving,  the  precipitate 
agglutinates,  and  forms  a  membranous  matter  of  a  grayish 
hue,  that  possesses  considerable  elasticity,  and  thus  ap¬ 
proaches  caoutchouc.  The  solutions  filtered  from  these 
bodies  strongly  tinge  those  of  the  sesqui-salts  of  iron. 
It  appears  that  tannin  solutions  react  in  a  similar  way 
with  protein  compounds  in  general. 

It  was  thought  for  a  long  time  that  the  insolubility  of 


38 


CHEMISTRY  OF  TANNING. 


the  tanno-gelatin  offered  a  means  for  insuring  the  purity 
of  tannin,  and  of  detecting  the  absence  or  presence  of 
gallic  acid  in  the  sources  affording  tannin ;  but  this 
insolubility,  excepting  in  water  alone,  does  not  answer 
the  purpose.  Pelouze  employed  a  piece  of  skin,  cleaned 
in  the  ordinary  way  from  hair  and  epidermis ;  this  was 
immersed  for  some  hours  in  the  extract,  and  the  whole 
agitated  occasionally,  and  finally  the  liquid  filtered. 
When  pure  tannin  was  operated  upon,  the  whole  com¬ 
bined  with  the  integument,  so  that  the  fluid  had  no 
astringent  taste,  nor  did  it  color  a  solution  of  a  sesqui- 
salt  of  iron ;  but  if  gallic  acid  had  been  mixed  with  it, 
the  bluish-black  tint  would  present  itself  in  the  latter 
case. 

Freshly  precipitated  alumina,  agitated  with  a  solution 
of  tannin,  absorbs  the  latter  rapidly  and  forms  with  it 
an  insoluble  compound ;  gallic  acid  behaves  i^  a  similar 
manner.  At  the  temperature  of  an  oil  bath,  tannic  acid 
is  decomposed,  water  and  carbonic  acid  being  formed ; 
but  when  the  heat  is  increased,  other  products  are 
generated,  and  nothing  remains  but  charcoal,  which,  if 
heated  on  platinum  wire,  burns,  leaving  no  residue. 
Strong  ether  dissolves  tannin,  and  forms  a  syrupy  liquid, 
which  does  not  combine  with  fresh  ether.  Alcohol 
behaves  with  tannin  in  the  same  way,  the  solvent  power 
of  the  spirit  decreasing  in  reference  to  it  as  it  ap¬ 
proaches  purity  or  dehydration. 

Composition. 

According  to  Berzelius,  tannin  such  as  it  was  pre¬ 
pared,  i.  e.,  impure,  was  composed  of  • 

Carbon  .......  52.69 

Hydrogen  .  .  .  .  .  .3.86 

Oxygen  .......  43.45 

100.00 

Pure  tannin,  according  to  Pelouze,  is  thus  formed : — 

Carbon  .......  51.40 

Hydrogen  .  .  .  .  .  .  3.51 

Oxygen  .......  45.09 


100.00 


PURE  TANNIN 


39 


These  numbers  nearly  correspond  with  the  formulae 
C1SHS012=  C18H5  093H0.  But  Strecker,  in  his  later 
researches,  gives  the  equation  thus,  C'4!!22^34,  showing 
that  it  contains  less  oxygen  and  hydrogen  than  is  indi¬ 
cated  above. 

Preparation. 

When  tannin  is  to  be  obtained  in  its.  greatest  state  of 
purity,  recourse  must  be  had  to  the  process  known  as 
that  of  Pelouze,  but  which  was  first  broached  by  Lam¬ 
bert.  The  latter  chemist  directed  the  formation  of  an 
extract  of  60  grains  of  powdered  nutgalls  in  120  grains 
of  ether,  the  digestion  to  be  continued  for  twenty-four 
hours,  after  which  the  ethereal  extract  was  to  be  filtered 
and  evaporated.  Pelouze  followed  the  foregoing  method 
in  principle  by  employing  the  apparatus  of  Robiquet 
and  Boutron  as  used  for  the  prepa¬ 
ration  of  Amygdalin.  Fig.  1  repre¬ 
sents  this  digester.  It  is  an  elon¬ 
gated  glass  vessel  A ,  having  an 
orifice  at  the  top,  which  is  lilted 
with  a  ground  glass  stopper,  and 
contracting  towards  the  other  ex¬ 
tremity,  which  fits  tightly  into  the 
neck  of  a  bottle  or  matrass  B  which 
receives  the  extract.  Sometimes 
the  lower  bottle  has  a  second  tubu¬ 
lar  opening,  _D,  for  the  purpose  of 
receiving  a  cork  furnished  with  a 
tube,  to  which  a  connector,  C,  of 
caoutchouc  is  appended,  the  other 
end  being  attached  to  a  similar 
tube  fitted  in  cork  which  closes  the 
top  orifice.  Between  F  G  is  the 
powdered  gall,  and  in  FI  is  a  little 
batting  of  cotton.  This  adaptation 
causes  the  filtration  to  take  place 
more  readily,  whilst  it  prevents 
contact  with  any  further  quantity 
of  air  beyond  what  is  contained  in 
the  apparatus.  Common  sulphuric  ether  is  then  poured 


Fig.  1. 


40 


CHEMISTRY  OF  TANNING. 


upon  the  galls,  and  as  it  traverses  the  powder  it  takes 
up  the  tannin  and  gallic  acid.  The  latter,  however, 
gives  a  lighter  and  more  fluid  solution  than  tannin,  and 
forms  the  upper  stratum  of  the  ethereal  solution  which 
has  traversed  the  galls  and  dropped  into  the  receiving 
bottle.  The  dense  and  dark-colored  stratum  below  con¬ 
tains  tannin.  The  galls  are  treated  successively  with 
new  quantities  of  ether  until  they  cease  to  yield  soluble 
matter.  The  several  ethereal  solutions  are  then  mixed 
together  and  poured  into  a  separating  funnel.  When 
the  two  strata  have  formed,  the  lower  one  containing 
the  tannin  is  drawn  off  into  a  retort,  distilled  to  save 
ether,  then  repeatedly  washed  with  pure  sulphuric  ether 
to  remove  traces  of  gallic  acid,  and  evaporated  over  a 
warm  sand-bath  or  under  the  receiver  of  an  air-pump ; 
the  tannin  is  obtained  in  the  form  of  a  spongy,  irides¬ 
cent,  uncrystallizable  mass  having  a  light  shade  yellow 
color.  So  prepared,  tannin  is  in  its  purest  known  state  ; 
but  as  sometimes  it  results  almost  colorless,  doubtless  it 
is  not  free  from  impregnation  arising  from  decomposed 
tannin,  apothema,  or  some  other  matters. 

Another  modification  of  the  method  just  detailed  was 
introduced  by  Domine,  and  offers  the  advantage  of  yield¬ 
ing  a  larger  product,  while  it  admits  also  of  being 
applied  on  the  large  scale  for  the  purpose  of  the  manu¬ 
facturer.  He  places  the  powdered  galls  in  a  damp  cellar 
for  several  days,  during  which  they  absorb  moisture ; 
the  powder  is  next  transferred  to  a  wide-mouthed  jar, 
and  made  into  a  paste  with  ether  of  a  specific  gravity 
0.75.  After  this  the  vessel  is  hermetically  closed,  and 
the  contents  allowed  to  digest  for  24  hours.  At  the 
expiration  of  this  time  the  pasty  contents  are  trans¬ 
ferred  to  a  strong  linen  bag  and  subjected  to  gradual 
pressure,  when  the  ethereal  extract  of  tannin,  having  a 
dark  syrupy  consistence,  flows  off  into  the  receiver. 
This  liquid  must  be  evaporated  to  dryness  at  a  gentle 
heat,  by  which  the  tannic  acid  is  left  in  the  form  of 
light-colored  resin-like  scales.  The  compressed  residue 
is  further  treated  with  ether,  to  which  six  per  cent,  of 
water  is  added  in  the  same  manner  as  when  preparing 


IMPURE  TANNIN. 


41 


the  first  extract,  and  on  expelling  the  fluid  by  a  gentle 
heat,  a  residue  of  tannin  is  obtained.  It  is,  indeed, 
more  impure  than  the  above,  as  it  contains  chlorophylle, 
volatile  oil,  and  gallic  acid ;  still  the  tannin  thus  pre¬ 
pared  answers  very  well  for  many  industrial  purposes. 


CHAPTER  II. 

IMPURE  TANNIN. 

CHEMICAL  PROPERTIES  OF  IMPURE  TANNIN — PREPARATION — VARIETIES 
IN  THE  IMPURE  TANNIN. 

Impure  tannin  is  solid,  brown,  transparent,  friable, 
uncrystallizable,  odorless,  has  a  very  astringent  taste ;  it 
is  heavier  than  water,  reddens  the  solution  of  litmus, 
softens  in  the  fingers,  melts  at  a  low  temperature ;  it  is 
very  soluble  in  water,  principally  while  warm  ;  by  cooling 
it  precipitates  a  light  yellowish  powder.  The  solution 
has  a  brown  color,  and  is  not  decomposed  when  exposed 
to  the  air  even  at  a  middling  temperature.  Little  solu¬ 
ble  in  absolute  alcohol,  it  dissolves  in  it  only  by  the 
addition  of  a  little  water  in  the  proportion  of  0.10. 
According  to  the  experiments  of  Proust,  Deyeux,  and 
Davy,  it  combines  with  oxygen,  but  then  it  is  decom¬ 
posed  or  altered  in  its  nature.  According  to  Bouillon- 
Lagrange,  it  is  transformed  by  this  absorption  into  gallic 
acid.  It  precipitates  albumen  and  gelatine  from  their 
dissolutions  and  forms  insoluble  combinations. 

Hydrochloric  and  sulphuric  acids  precipitate  the  aque¬ 
ous  solution  of  impure  tannin  ;  the  precipitate,  which  is 
very  slightly  soluble  in  cold  water,  but  very  soluble  in 
hot  water  and  alcohol,  is  a  combination  of  tannin  with 
the  acid  employed. 

Acetic,  arsenic,  malic,  oxalic,  and  tartaric  acids  pre¬ 
cipitate  the  infusion  of  nutgalls  ;  this  precipitate,  washed 
with  cold  water  and  dissolved  in  boiling  water,  has  all 
the  properties  of  tannin.  Nitric  acid  and  chlorine  de¬ 
stroy  it  easily  ;  the  first  transforms  it  into  a  brown  yellow¬ 
ish  substance,  soluble  in  alcohol  and  similar  in  its  pro-' 
perties  to  an  extract.  According  to  Proust,  it  is  the  same 


42 


CHEMISTRY  OF  TANNING. 


for  the  stannic  acid.  Pure  and  carbonated  alkalies 
form  with  this  substance  combinations  nearly  insoluble. 
Metals  have  not  a  sensible  action  on  impure  tannin,  but 
the  greatest  number  of  oxides  combine  with  it  and  ren¬ 
der  it  insoluble  in  water. 

Baryta  and  lime-waters  decolorize  the  solution  of  im¬ 
pure  tannin  and  produce  a  precipitate  which  is  a  combi¬ 
nation  of  tannin  with  the  oxide ;  this  precipitate  is 
nearly  insoluble  in  water  and  without  action  on  gelatine ; 
it  differs  from  the  combination  of  this  last  substance  with 
the  tannin  in  which  they  cannot  be  separated,  because 
they  form  a  new  compound.  In  the  combination  of  the 
tannin  with  an  alkali  or  earth  it  can  be  isolated  by 
treating  the  combination  by  an  acid  which  dissolves  the 
oxide  and  sets  free  the  tannin. 

By  agitating  recently  precipitated  magnesia  or  alu¬ 
mina  in  a  solution  of  tannin,  it  forms  a  tannate  of  mag¬ 
nesia  and  alumina,  insoluble  in  water  and  decomposable 
by  acids  which  render  the  tannin  soluble  in  that  liquid. 
If  we  treat  the  infusion  of  nutgalls  by  baryta,  strontia,  or 
lime-waters,  the  precipitate  has  an  olive  color,  and  is 
composed  of  tannate  and  gallate  united  with  the  extrac¬ 
tive. 

If  we  boil  magnesia  with  an  infusion  of  nutgalls,  the 
precipitate  has  a  dirty  yellow  color,  insoluble,  composed 
of  tannin,  extractive,  and  magnesia,  while  the  gallate 
of  magnesia  stays  dissolved  in  the  liquor. 

Alumina  in  small  proportions  gives  the  same  results ; 
in  large  quantities  it  separates  all  the  substances  which 
constitute  the  infusion.  The  alkaline  carbonates  sepa¬ 
rate  from  the  gallic  infusion  the  tannin  and  extractive  ; 
the  formed  gallate  stays  in  solution  ;  the  solution  of  tan¬ 
nin  does  not  decompose  salts  of  the  first  section,  but  on 
the  contrary  it  operates  the  decomposition  of  many  be¬ 
longing  to  the  four  last. 

In  solution  of  copper  it  produces  an  olive  precipitate. 

In  sulphate  of  manganese  it  produces  a  fine  light  green 
precipi tate. 

In  nitrate  of  mercury  the  precipitate  is  light  yellow. 

In  that  of  titanium  it  is  blood  red. 


IMPURE  TANNIN. 


43 


In  binoxide  of  iron  it  is  bluish. 

In  ter  oxide  of  iron  it  is  gray  black. 

Tannin  unites  and  forms  combinations  nearly  insolu¬ 
ble  with  some  other  principles,  such  as  starch,  glutin, 
ligneous  fibre,  albumen,  casein,  mucus,  etc.  Tannin 
submitted  to  the  action  of  the  heat  swells  and  is  decom¬ 
posed  ;  by  distillation  it  gives  a  black  liquor  which 
precipitates  black  the  dissolutions  of  iron.  This  pre¬ 
cipitation  is  due  to  a  little  pyrogallic  acid.  The  residue 
in  the  retort  is  a  very  voluminous  charcoal  which 
amounts  to  0.0263  of  the  decomposed  tannin. 

Preparation  of  Tannin  from  Nutgalls. 

In  the  art  of  tanning,  the  decoction  used  contains, 
besides  tannin,  gallic  acid,  extractive,  and  other  soluble 
vegetable  principles.  Different  processes  have  been  pro¬ 
posed  to  isolate  it ;  they  do  not  produce  it  pure,  but  in 
a  state  sufficiently  so  for  many  purposes. 

Proust's  Process. 

This  chemist  advises  exhaustion  of  the  nutgalls  by 
water,  and  to  pour  into  the  liquor  a  dissolution  of  hydro¬ 
chlorate  of  tin  till  it  does  not  prcipitate.  Proust  called 
this  precipitate  tannate  of  tin ;  it  is  yellowish-white. 
When  washed  and  diluted  in  cold  water  he  passes 
through  it  a  current  of  hydrosulphuric  acid  gas,  filters, 
and  evaporates  to  dryness.  According  to  this  chemist 
it  is  pure  tannin,  but  it  has  been  ascertained  that  it  con¬ 
tains  a  little  gallic  and  hydrochloric  acids  and  extractive 
matter. 

Deyeux's  Process. 

He  makes  a  strong  infusion  of  nutgalls  and  precipi¬ 
tates  it  with  a  concentrated  solution  of  carbonate  of 
potash.  He  obtains  an  abundant  precipitate,  yellowish- 
white,  which  by  drying  forms  a  whitish  powder.  This 
product  is  far  from  being  pure.  Davy  and  Tromsdorff 
have  ascertained  it  was  a  combination  of  tannin,  gallic 
acid,  carbonate  of  potash,  and  lime. 


44 


CHEMISTRY  OF  TANNING. 


Dize’s  Process. 

This  chemist  has  ascertained  that  by  pouring  concen¬ 
trated  sulphuric  or  hydrochloric  acid  into  a  concentrated 
infusion  of  nutgalls,  a  white  precipitate  was  obtained. 
Proust  considers  it  like  a  combination  of  tannin  with 
the  acid  employed.  To  purify  it,  it  is  sufficient  to  wash 
it  with  cold  water,  dissolve  it  in  warm  water,  and  satu¬ 
rate  the  acid  by  carbonate  of  potash.  This  tannin  is 
not  pure.  Besides  the  extractive  precipitated  by  sul¬ 
phuric  acid,  it  contains  gallic  acid. 

Merat-Guillot’s  Process. 

He  precipitates  the  infusion  of  nutgalls  by  lime-water, 
and  treats  the  precipitate  by  diluted  nitric  or  hydro¬ 
chloric  acid.  An  effervescence  is  produced,  and  the 
liquor  takes  a  dark  color.  The  filtration  separates  a 
bright  black  substance  that  this  chemist  calls  pure 
tannin,  but  as  Davy  has  demonstrated  it  is  united  with 
extractive  combined  with  lime. 

Bouillon- Lagrange’ s  Process. 

His  method  consists  in  precipitating  the  infusion  of 
galls,  by  carbonate  of  ammonia,  washing  the  precipitate 
with  cold  water,  and  digesting  repeatedly  in  fresh  por¬ 
tions  of  alcohol  at  0.817.  This  process  is  as  defective 
as  the  others. 

Tromsdorff' s  Process. 

He  infuses,  for  three  days,  at  a  temperature  of  65°  a 
mixture  of 

Powdered  nutgalls  ....  3  lbs. 

Water . 5  gals.^ 

Stir  often,  filter,  add  a  new  quantify  of  water,  and 
repeat  the  operation  until  the  liquor  does  not  precipitate 
with  sulphate  of  iron.  Mix  all  the  liquors,  evaporate 
them  at  a  gentle  heat,  and  filter  through  a  cloth  to  sepa¬ 
rate  the  extractive.  Evaporate  anew  until  it  has  the 
consistence  of  a  jelly,  and  dry  in  the  oven  ;  treat  several 
times  with  alcohol  at  0.796  till  it  does  not  contain  gallic 


IMPURE  TANNIN. 


45 


acid.  For  this  purpose  he  treats  the  tannin  twice  by 
alcohol  at  0.10.  It  then  contains  a  little  mucous  and 
extractive  matter.  To  separate  them  he  dissolves  the 
tannin  in  water  and  exposes  it  to  the  air.  It  forms  a 
moisture  that  he  separates  by  filtration  and  evaporates 
to  dryness.  The  residue  is  pure  tannin,  containing, 
however,  a  little  sulphate  of  lime;  to  eliminate  it  he 
dissolves  it  in  water  and  adds  carbonate  of  potash  until 
no  more  precipitate  is  formed.  He  filters,  and  to  the 
dissolution  he  adds  acetate  of  lead,  which  forms  a  pre¬ 
cipitate  or  combination  of  tannin  with  oxide  of  lead. 
He  washes  the  precipitate,  and  when  dry  makes  a  paste 
with  it  and  water,  and  decomposed  with  sulphuretted 
hydrogen  gas  to  separate  the  oxide  of  lead  at  the  state 
of  sulphuret.  He  evaporates  the  filtrate  to  dryness. 
The  tannin  is  as  pure  as  it  was  possible  to  obtain  it  at 
that  time. 


Ser turner’s  Process. 

This  chemist  precipitates  the  alcoholic  infusion  of 
nutgalls  by  warm  carbonate  of  potash.  He  decants  and 
washes  the  residue  with  alcohol,  he  dissolves  in  water, 
separates  the  carbonate  of  potash  by  sulphuric  acid, 
evaporates  and  treats  the  residue  with  alcohol.  The 
excess  of  sulphuric  acid  is  precipitated  by  carbonate  of 
lime.  He  filters  and  evaporates  the  filtrate  to  dryness. 
The  residue  is  tannin  containing  very  little  gallic  acid. 

These  different  processes  are  for  giving  pure  tannin ; 
for  the  properties  to  be  astringent,  soluble  in  water,  and 
precipitate  the  gelatine  belong  to  some  other  substances 
of  a  different  nature  which  are  confounded  in  the 
generic  name  of  tannin. 

Varieties  of  Impure  Tannin. 

We  have  said  that  notwithstanding  the  numerous 
works  of  the  old  chemists,  they  never  succeeded  in 
obtaining  pure  tannin.  It  was  impossible  for  them  to 
separate  it  from  foreign  substances  principally  from  the 
extractive  with  which  it  forms  a  very  intimate  combina¬ 
tion,  as  it  is  to  the  extractive  that  were  due  the  varie- 


46 


CHEMISTRY  OF  TANNING. 


ties  observed  in  the  different  tannins.  The  less  impure 
was  that  extracted  from  grape-seeds  ;  as  that  of  nutgalls 
it  precipitates  the  gelatine  in  blue  white. 

That  of  sumac  precipitates  it  yellow. 

“  “  quinquina  “  “  DARK  ROSE. 

“  “  catechu  “  “  DARK-BROWN  RED. 

That  of  Brazil  wood  forms  with  gelatine  a  precipitate 
very  soluble  in  water. 

Proust  affirms  that  there  exist  several  varieties  of 
tannin,  but  it  is  very  probable  that  these  varieties  are 
combinations  of  tannin  with  the  above  substances.  In 
many  cases,  tannin  has  much  analogy  with  gallic  acid ; 
it  is  nearly  impossible  to  completely  deprive  it  of  the 
latter,  at  least  they  have  the  property  in  some  circum¬ 
stances  of  being  transformed,  the  tannin  into  gallic  acid, 
and  the  gallic  acid  into  tannin. 

The  moulded  infusion  of  nutgalls  gives  more  gallic 
acid  than  fresh  infusion,  by  treating  it  with  absolute 
alcohol.  This  example  proves  that  the  tannin  can  be 
transformed  into  gallic,  and  reciprocally. 

Tannin  of  Catechu. 

Davy  has  indicated  the  following  process  for  extract¬ 
ing  tannin  from  catechu.  He  treats  it  by  alcohol,  evapo¬ 
rates  the  extract,  treats  the  residue  by  water,  and 
evaporates  to  dryness.  This  tannin  is  astringent,  sweet¬ 
ish,  soluble  in  water  and  alcohol ;  the  dissolution  is  of  a 
dark-red  brown.  Potash,  ammonia,  magnesia,  increase 
the  color  without  precipitation.  Sulphuric  and  hydro¬ 
chloric  acids  precipitate  it  pale  brown.  The  salts  of 
protoxide  of  iron  are  not  precipitated  by  this  tannin. 
Those  of  peroxide  of  iron  are  precipitated  olive-green ; 
starch,  gluten,  ligneous  fibre,  gelatine,  albumen,  form 
with  it  an  insoluble  precipitate. 

Tannin  of  Bark  of  Trees — Sumac — Kino. 

Tannin  from  bark  of  trees  is  not  different  from  that 
from  nutgalls.  The  others  have  more  or  less  analogy 
with  those  of  catechu  or  nutgalls. 


IMPURE  TANNIN. 


47 


Tannin,  according  to  the  nature  of  the  substance  from 
which  it  is  extracted,  precipitates  the  dissolution  of  iron 
in  blue  or  green,  which  is  an  indication  of  a  variation 
in  its  constituents.  The  following  table  indicates  the 
principal  tannins  which  give  these  two  precipitates. 

1.  Tannin  which  forms  a  bluish-black  precipitate 

IN  SOLUTIONS  OF  A  SESQUI-SALT  OF  IRON : — 

Tannin  from  nut  galls , 

“  “  the  barks  of  oak,  beech,  poplar,  hazel,  chest¬ 

nut ,  maple,  horse-chestnut,  cherry ,  apricot, 
plum ,  elder,  winter,  and  other  barks. 

“  “  the  bark  of  sumac. 

“  “  logwood. 

“  “  roots  of  lithrum,  salicaria,  iris,  pseudocorus , 

geum  urbanum ,  polygonum  bistortum ,  al- 
chemilla  vulgaris. 

“  “  the  leaves  of  the  arbutus  uva  ursi,  amo- 

thera  biennis,  geranium  pratense,  etc. 

“  “  the  husks  of  the  ceesalpina  coriaria. 

“  “  lentils,  etc. 

2.  Tannin  which  forms  a  green  precipitate  in  the 

DISSOLUTION  OF  IRON. 

Tannin  from  catechu  (juice  of  the  Mimosa  catechu). 

“  “  kino  (juice  of  the  Coccoloba  uvifera). 

“  “  cinchona  barks. 

“  “  the  roots  of  the  rumex  aquaticus,  tormentilla 

erecta,  polypodium  filix  mas. 

“  “  the  tea  and  badiane. 


CHAPTER  III. 

ARTIFICIAL  TANNIN. 

PROPERTIES — COMPOSITION — FIRST  VARIETY — SECOND  VARIETY _ THIRD 

VARIETY — PREPARATION  OF  AN  ARTIFICIAL  TANNIN  FROM  TURF. 

Properties. 

Besides  the  foregoing,  chemists  distinguish  other  va¬ 
rieties  of  tannin,  which  result  from  the  chemical  action 


48 


CHEMISTRY  OF  TANNING. 


of  several  powerful  agents  upon  many  substances ;  as, 
for  instance,  from  the  action  of  nitric  acid  upon  char¬ 
coal  and  indigo,  and  likewise  from  the  effects  of  sul¬ 
phuric  acid  upon  resin  and  camphor.  The  first  notice 
of  artificial  tannin  was  published  by  Hatchett  in  the 
Transactions  of  the  Royal  Society  in  1801 ;  he  dis¬ 
covered  it  whilst  making  experiments  upon  the  slow  car¬ 
bonization  of  plants.  This  tannin  is  different,  however, 
from  other  varieties  of  this  substance  at  present  known. 

Artificial  tannin  is  a  brown  inodorous  substance, 
having  a  vitreous  fracture,  and  very  soluble  in  water. 
Thompson  states  that  alcohol  of  sp.  gr.  0.80  dissolves  it, 
and  so  far  it  manifests  a  difference  of  behavior  from 
natural  tannin.  The  aqueous  solution  of  this  substance 
precipitates  gelatine  of  a  brown  color,  but  the  shade 
deepens  as  the  liquids  are  more  dense.  This  precipitate 
is  a  compound  of  tannin  and  gelatine,  in  the  proportion 
of  36  parts  of  the  former  to  64  of  the  latter.  It  is  in¬ 
soluble  both  in  hot  and  cold  water.  With  the  alkaline 
bases  it  combines,  forming  more  highly  colored  solu¬ 
tions,  which  in  the  course  of  time  get  cloudy.  The 
ammoniacal.  solution  of  artificial  tannin  on  being  evapo¬ 
rated  to  dryness  and  redissolved  will  not  precipitate 
with  gelatine  till  after  the  alkali  which  it  retained  is 
neutralized  with  an  acid.  The  alkaline  earths  precipi¬ 
tate  it,  but  the  precipitates  are  slightly  soluble  in  water  ; 
the  heavy  oxides  precipitate  it  in  combination  as  a  pure- 
colored  substance.  On  treating  the  precipitate  with 
nitric  acid  the  artificial  tannin  dissolves  without  change, 
whereas  the  natural  product  is  altered  by  this  agent. 
Heated  alone  in  a  retort  it  yields  water  and  nitric  acid, 
ammonia,  carbonic  acid,  and  another  gaseous  substance, 
probably  nitrogen. 


of 


Composition. 

According  to  M.  Chevreul  artificial  tannin  is  formed 
Carbon  "] 

Hydroqen  !  .  ,  .  .  , 

.  >  in  undetermined  proportions. 

(Joey. gen  [  1  1 

Nitrogen  J 


ARTIFICIAL  TANNIN. 


49 


First  Variety. — Digest  diluted  nitric  acid  on  pow¬ 
dered  charcoal  till  entirely  dissolved.  The  proportions 
are 

Charcoal  .....  1  part. 

Nitric  acid  at  1.40  ...  5  parts. 

Water  .....  10  “ 

Mix  the  acid  with  the  water  and  treat  the  charcoal  in 
flasks  that  you  heat  in  the  air.  A  quick  effervescence 
takes  place  due  to  the  disengagement  of  nitrous  acid. 
After  a  digestion  of  a  few  days  add  nitric  acid  and  leave 
to  digest  until  the  carbon  is  dissolved.  Evaporate  to 
dryness  and  a  brown  mass  is  obtained,  which  is  the 
artificial  tannin.  By  this  process  you  obtain  99  grains 
of  artificial  tannin  from  88  grains  of  charcoal. 

Second  Variety. — This  process  consists  in  treating 
some  substances  rich  in  carbon,  as  indigo,  resin,  etc., 
with  nitric  acid.  The  dissolution  of  indigo  in  nitric 
acid  gives  a  residue  with  an  orange  color,  very  bitter, 
soluble  in  water,  forms  with  gelatine  an  insoluble  pre¬ 
cipitate,  and  has  an  action  similar  to  tannin  on  metallic 
salts.  This  variety  contains  nitrous  acid. 

Third  Variety. — Is  obtained  by  dissolving  camphor 
and  resins  in  sulphuric  acid  and  leaving  them  together 
till  the  liquor  becomes  black,  adding  cold  water,  which 
precipitates  a  black  powder,  which  is  digested  in  alcohol. 
By  evaporation  a  black  substance  soluble  in  water  and 
alcohol  is  obtained.  It  forms  an  insoluble  precipitate 
with  gelatine,  and  has  a  weak  action  on  salts  of  iron. 
According  to  M.  Chevreul  this  tannin  contains  hyposul- 
phuric  acid. 

Preparation  of  a  Tannin  from  Turf 

Mr.  H.  C.  Jennings  has  prepared  a  tannin  from  turf 
in  the  following  manner:  He  takes  black  turf  and 
moulds  it  into  small  bricks  from  2  to  4  inches  thick,, 
and  exposes  them  to  the  air  until  dry.  He  reduces 
them  to  fine  powder,  introduces  into  a  vessel  and 
moistens  the  surface  with  nitric  acid  from  10  to  20  per 
4 


50 


CHEMISTRY  OF  TANNING. 


cent,  of  the  weight  of  the  turf,  stirring  well.  The  mix¬ 
ture  becomes  warm  and  swells. 

When  red  nitrous  vapors  appear  he  hermetically 
shuts  the  vessel  and  leaves  until  all  vapors  have  disap¬ 
peared,  then  he  adds  6  to  10  times  the  weight  of  water 
and  stirs  well. 

When  the  mixture  is  thoroughly  homogeneous  he 
treats  it  with  boiling  water.  The  tannin  dissolves  in 
the  water. 

Mr.  Jennings  has  ascertained  that  leather  can  be 
tanned  with  this  tannin,  but  after  its  use  the  skins  must 
be  dipped  in  a  solution  composed  of  30  to  40  parts  of 
carbonate  of  soda  in  100  of  water. 


CHAPTER  IV, 

TANNIN  FROM  VARIOUS  SOURCES. 

It  is  demonstrated  that  several  substances  by  com¬ 
bining  with  certain  acids,  produce  natural  and  artificial 
tannin.  The  combination  of  an  acid  is  indispensable 
for  the  existence  of  tannin,  or  rather  tannin  is  not  an 
immediate  principle,  but  the  compound  of  a  peculiar 
substance  and  an  acid  united  with  more  or  less  ex¬ 
tractive  matter. 

1.  Thus  the  tannin  of  nutgalls,  of  the  barks  of  oak, 
sumach,  etc.,  is  united  with  gallic  acid  in  greater  or  less 
proportion.  It  is  very  difficult  to  separate  them,  and 
wTe  believe  that  it  is  to  the  gallic  acid  that  is  due  the 
black  precipitate  formed  by  tannin  in  salts  of  sesqui- 
oxide  of  iron.  This  acid  plays  an  active  part  in  tan¬ 
ning.  Its  action  has  not  yet  been  studied.  The  older  the 
vegetable  substances,  the  more  gallic  acid  they  contain, 
and  consequently  less  tannin. 

2.  Artificial  tannin  is  always  combined  with  nitric  or 
sulphuric  acid,  according  to  the  acid  used. 

3.  It  is  in  acid  fruits  that  tannin  is  found;  in  this 
case  it  is  united  with  gallic  acid  and  even  with  the  acid 
from  the  fruit. 

Chemists  name  four  kinds  of  tannin. 


GALLIC  AND  ELLAGIC  ACIDS. 


51 


1.  Natural  tannin,  presenting  several  varieties,  ac¬ 
cording  to  the  proportions  of  extractive  matter  and 
gallic  acid. 

2.  Artificial  tannin  resulting  from  the  action  of  nitric 
acid  on  charcoal. 

3.  Artificial  tannin  resulting  from  the  action  of  nitric 
acid  on  indigo,  resins,  etc. 

4.  Artificial  tannin  resulting  from  the  action  of  sul¬ 
phuric  acid  on  rosin  or  camphor. 

In  the  present  state  of  things  it  is  not  rational  to 
confound  artificial  with  natural  tannin,  and  the  above 
statement  is  sufficient. 


CHAPTER  Y. 

GALLIC  AND  ELLAGIC  ACIDS. 

GALLIC  ACID — PREPARATION — CHEMICAL  PROPERTIES — COMPOSITION — 

ELLAGIC  ACID. 

GALLIC  ACID. 

The  tendency  of  Tannin  to  be  transformed  into  gallic 
acid  has  been  already  mentioned ;  but  it  may  be  well  to 
show  more  in  detail  the  circumstances  under  which  this 
change  is  effected,  and  to  point  out  the  properties  of 
gallic  acid  generally,  as  also  with  regard  to  the  opera¬ 
tions  of  the  tanner.  Its  name  has  been  derived,  as  is 
evident,  from  galls,  on  account  of  those  excrescences 
containing  it  ready  formed.  It  likewise  exists  in  cy¬ 
press  nut,  arnica  flowers,  white  hellebore,  meadow  saffron, 
colchicum  autumnale ,  and  in  a  number  of  astringent 
barks  together  with  tannic  acid,  but  in  small  quantities. 
Its  most  prolific  source  is  tannic  acid,  which  by  oxida¬ 
tion  yields  it  abundantly.  The  conditions  affecting  the 
change,  such  as  exposure  of  the  solution  of  tannin  to 
air  and  at  an  increased  temperature,  have  been  already 
mentioned,  as  likewise  the  decomposition  of  the  same 
body  by  the  mineral  acids.  All  the  methods  recom¬ 
mended  for  the  production  of  gallic  acid  from  tannin 
are  based  upon  these  properties  of  the  latter. 


52 


CHEMISTRY  OF  TANNING. 


Preparation. 

Scheele’s  Process. — He  makes  a  concentrated  aqueous 
solution  of  nutgalls,  filters  and  leaves  exposed  to  con¬ 
tact  with  the  air.  Tannin  is  decomposed  little  by  little, 
and  gives  place  to  a  moulding,  which  is  taken  after  one 
or  two  months ;  he  takes  out  the  yellowish  or  grayish 
deposit  from  the  bottom  of  the  vasis  and  dissolves  it  in 
boiling  water ;  he  filters,  and  by  a  gentle  evaporation, 
obtains  gallic  acid  in  the  form  of  brownish  crystals. 
He  redissolves  it  several  times  in  boiling  water,  and 
purifies  it  with  a  little  animal  black. 

Fiedler  s  P-ocess. — In  one  pint  of  water  he  boils  one 
ounce  of  nutgalls,  filters,  and  adds  to  the  liquor  a  solu¬ 
tion  of  two  ounces  of  alum,  the  alumina  of  which  has 
been  precipitated  by  carbonate  of  soda.  He  stirs  the 
mixture  and  leaves  it  in  till  the  next  day.  The  pre¬ 
cipitate  is  treated  with  hot  water  until  it  does  not 
blacken  sulphate  of  iron.  He  reunites  the  liquors  and 
evaporates  so  as  to  obtain  crystals  by  cooling. 

Braconnofs  Process. — Take  powdered  nutgalls  and 
pour  on  them  water  in  sufficient  quantity  to  cover  them, 
and  then  leave  at  a  temperature  of  70°  to  75°.  After 
a  while  a  quick  action  takes  place,  and  when  this  sub¬ 
sides  the  paste  is  expressed  and  treated  with  boiling 
water,  which  dissolves  the  gallic  acid  and  yields  it  upon 
evaporation  in  impure  crystals.  These  by  re-solution 
in  water  and  filtration  of  the  liquid  through  animal 
black  afford  a  menstruum  which  gives  the  gallic  acid  in 
a  state  of  purity  when  concentrated. 

lire’s  Process. — In  a  strong  solution  of  nutgalls  pour 
hydrochlorate  of  tin  until  no  more  precipitate  is  formed. 
Filter,  dilute  the  matter  in  water  and  pass  through  it  a 
current  of  hydrosulphuric  acid  gas,  filter,  evaporate; 
crystals  of  gallic  acid  deposit  by  evaporation. 

It  would  appear  from  various  researches  that  the 
change  of  tannin  to  gallic  acid,  on  exposing  the  extract 
containing  the  former  to  air  and  moisture,  is  due  to  a 
fermentative  process,  which  is  considerably  expedited  if 
the  vegetal  matter  in  the  bark  or  gall,  or  whatever  else 


GALLIC  AND  ELLAGIC  ACIDS.  '  53 

the  source  may  be,  is  permitted  to  remain  in  contact 
with  the  liquid.  Such  is  the  case,  especially  with  the 
extract  of  gall-nut ;  and  it  may  be  inferred  that  the 
tannin  from  all  other  sources,  and  which  is  capable  of 
being  transformed  into  gallic  acid  by  oxidation  in  the 
above  manner,  is  similarly  affected.  Mr.  Laroche  has 
shown  by  comparative  experiments  the  effect  of  the 
marcs  of  gall-nuts  after  the  extraction  of  the  tannin 
with  ether  in  the  ordinary  way  in  operating  this  change. 
By  inclosing  an  aqueous  solution  of  tannin  and  a  por¬ 
tion  of  this  residue  in  a  bottle  or  flask,  and  allowing  it 
to  remain  for  some  time,  he  found  that  the  tannin  was 
entirely  converted  into  gallic  acid,  whilst  a  strong  ex¬ 
tract  of  tannin,  freely  exposed  to  the  air  at  the  same 
time,  retained  nearly  the  whole  of  its  tannin  unaltered. 
Hence,  doubtless,  the  insoluble  matter  in  galls  in  the 
presence  of  moisture,  is  capable  of  acting  on  tannin  as 
a  ferment,  and  that  the  change  of  tannin  into  its  deriva¬ 
tives  is  the  result  of  a  fermentation.  It  is  well  known 
that  fermentation  by  contact  of  yeast,  blood,  and  albu¬ 
men  effects  the  same  transformation  of  the  astringent  ex¬ 
tract  as  the  residue  of  the  galls  which  have  been  digested 
in  ether,  and  also  that  the  latter  will  excite  the  various 
fermentations  in  solutions  of  grape  sugar,  and,  therefore, 
these  reactions  may  be  taken  as  mutually  corroborative. 
Further,  the  gallic  fermentation  may  be  intercepted  by 
antiseptics  like  the  vinous.  Protochloride  of  mercury 
completely  prevents  the  decomposition;  and  pyrolig¬ 
neous  acid,  or  carbonic  acid,  on  account  of  some  aro¬ 
matic  matters  which  it  contains,  likewise  considerably 
retards  the  fermentation. 

It  has  been  shown  that  sulphuric  and  hydrochloric 
acids  at  a  boiling  heat  rapidly  change  tannin  into  gallic 
acid,  and  without  the  intervention  of  air ;  but  if  the 
mixture  be  kept  at  a  common  temperature,  Mr.  Antoine 
has  shown  by  his  researches  that  the  decomposition  of 
the  tannin  is  retarded  by  a  small  quantity  of  these  acids. 
On  the  contrary,  malic,  tartaric,  and  vegetable  acids  in 
general,  expedite  the  decomposition  of  the  tannin.  The 


54 


CHEMISTRY  OF  TANNING. 


rapidity  with  which  sumach  ferments  may  be  referred 
to  the  quantity  of  malic  acid  it  contains. 

Properties. 

When  pure,  this  acid  crystallizes  in  long  silky  nee¬ 
dles,  which  are  unalterable  in  the  air  ;  its  taste  is  acrid 
and  styptic.  Braconnot  states  that  it  dissolves  in  a 
hundred  parts  of  cold  and  in  about  three  parts  of  hot 
water,  four  or  five  parts  of  alcohol  in  the  cold  dissolve 
it,  but  one  part  of  the  hot  spirit  will  take  it  up.  It  is 
soluble  in  ether,  but  in  less  quantity.  The  aqueous 
and  spirituous  solutions,  but  the  former  more  readily, 
undergo  decomposition,  so  that  the  surface  of  the  liquid 
becomes  mouldy,  and  a  brownish  matter  is  produced,* 
which  Daeboereiner  considers  ulmin.  Added  to  a  solu¬ 
tion  of  gelatine  no  precipitation  occurs,  a  behavior  which 
at  once  distinguishes  gallic  from  tannic  acid,  and  which 
indicates  that  it  is  unavailable  in  converting  skin  into 
leather.  This  being  so,  and  as  has  been  already  pointed 
out,  tannin  being  readily  convertible  into  this  body,  it 
becomes  of  the  utmost  importance  to  the  tanner  to  guard 
against  this  transformation,  which,  in  the  usual  way  of 
tanning,  is  so  apt  to  take  place.  The  researches  of 
Larocque  have  shown  that,  as  regards  the  tannin  from 
galls,  the  decomposition  is  completely  and  readily  ef¬ 
fected,  provided  the  insoluble Tesiduary  matter  be  allowed 
to  remain  in  contact  with  the  liquor  containing  the  tan¬ 
nic  acid,  and  it  is  equally  well  known  that  the  tannin 
from  sumach  is  liable  to  decomposition,  as  well  when  it 
remains  in  contact  with  the  insoluble  portion  of  this  body 
as  when  it  is  separated  from  it ;  but  independently  of 
the  action  of  the  residue,  the  malic  acid  here  plays  an 
important  part.  Though  the  evidence  proving  that  the 
insoluble  portion  of  the  barks,  etc.,  employed  in  tanning 
when  allowed  to  remain  in  the  tan  liquor,  does  operate  in 
the  rapid  conversion  of  tannin  into  gallic  acid  ;  thereby 
rendering  the  former  valuable  body  useless  is  not  definite. 
Still  knowing  that  in  the  waste  tan  liquor  a  large  quan¬ 
tity  of  gallic  acid  is  found,  it  may  be  safely  stated  that 
its  production  is  from  the  tannin,  and  also  is  owing  more 


GALLIC  AND  ELLAGIC  ACIDS. 


55 


to  the  effects  of  the  insoluble  matter  of  the  source  of  the 
tannin  than  to  any  oxidation  which  takes  place  during 
the  tanning  processes.  Even  those  kinds  of  tannin  which 
are  incapable  of  producing  gallic  acid  by  decomposition, 
are  subject  to  a  metamorphosis  which  destroys  the  tan¬ 
ning  agent,  and  this  fermenting  action  is  more  readily 
produced  where  the  insoluble  matter  is  left  in  contact, 
than  if  the  liquor  were  retained  by  itself.  The  only 
benefit  that  the  tanner  derives  from  gallic  acid  is  that 
it  aids  in  swelling  the  hides,  and  thus  facilitates  the  ab¬ 
sorption  of  the  tannin ;  but  when  it  is  considered  that  a 
dilute  solution  of  sulphuric  or  vegetal  acids  effects  the 
same  thing  quite  as  well,  it  will  be  evident  that  he  who 
relies  on  the  swelling  by  gallic  acid,  and  sacrifices  a  cor¬ 
responding  portion  of  tannin  in  its  production,  suffers  a 
considerable  loss,  and  is  unable  to  compete  with  those 
who  can  obviate  such  a  sacrifice. 

At  410°  to  420°,  according  to  the  observations  of  M. 
Pelouze,  gallic  acid  is  entirely  volatilized,  producing  a 
sublimate  of  beautiful  white  crystals  and  pure  carbonic 
acid.  If  the  heat  be  urged  to  464°  or  482°,  instead  of 
the  foregoing  change,  another  takes  place,  in  which  pure 
carbonic  acid  is  likewise  developed.  ,  But  in  addition  to 
this  a  quantity  of  water  is  produced,  and  which  runs 
along  the  sides  of  the  retort,  in  the  bottom  of  which 
remains  a  considerable  mass  of  brilliant  black  insoluble 
matter,  which  at  first  sight  might  be  taken  for  charcoal. 
It  is,  however,  a  true  acid,  and  is  called  by  Pelouze 
metarjallic  acid. 

The  aqueous  solution  of  gallic  acid,  upon  treatment 
with  potash,  soda,  or  ammonia,  assumes  a  reddish-yellow 
color,  which  turns  to  deep  brown  by  exposure  to  the  air, 
probably  by  the  absorption  of  oxygen.  By  the  use  of 
alcohol  as  a  solvent  and  certain  precautions,  definite, 
crystallized,  and  soluble  compounds  of  the  acid  with  these 
bases  may  be  formed.  If  the  acid  is  associated  with 
tannin,  it  decomposes  nearly  all  metallic  salts.  With 
baryta,  strontia,  and  lime,  it  forms  slightly  soluble  com¬ 
pounds.  Its  affinity  for  magnesia  is  very  strong,  and  the 
compound  which  it  forms  with  that  earth  is  insoluble  in 


56 


CHEMISTRY  OF  TANNING. 


water,  but  soluble  in  an  excess  of  acid.  Gallic  acid  is 
also  neutralized  by  alumina. 

Gallic  acid  precipitates 


Soluble  salts  of  mercury 

“  “  COPPER 

“  “  BISMUTH 

“  “  LEAD 

“  “  PROTOXIDE  OF  IRON 

“  “  SESQUI  “  “ 


in  or  any  e-yellow. 

“  brown. 

“  lemon. 

“  white. 

“  blue. 

“  dark  blackish-blue. 


Composition. 

According  to  Pelouze  crystallized  gallic  acid  is  com¬ 
posed  of 

Carbon  .  .  .  .  50.10 

Hydrogen  .  .  .  .  3  64 

Oxygen  .  .  .  .  46.26 


100.00 

Numbers  which  agree  with  the  formula  C7H305H0. 
Strecker,  however,  regards  it  as  a  tribasic  acid ;  thus, 
C14HuO102HO=3HO,C14H3O72Aq,  and  capable  of  form¬ 
ing  salts  which  correspond  with  the  general  formula 

MO,2HO,  C14H307 ;  2MO,HO,C14H;A,  and  3M0,CUH3 
07 ;  MO  being  the  representative  of  a  metallic  oxide. 

As  pyrogallic  acid,  C7H303  or  C14H606,  metagallic  acid 
CvH202  or  C14H404,  ellagic  acid  C14H207H0  and  other 
derivatives  of  gallic  acid,  and,  therefore,  remotely  from 
tannic  acid,  are  of  no  importance  in  the  making  of 
leather,  they  will  not  be  further  dwelt  upon. 

ELLAGIC  ACID. 

Extract  of  gall,  exposed  for  a  long  time  to  the  air, 
contains  in  addition  to  gallic  acid  another  acid,  inso¬ 
luble  in  water  and  to  which  the  name  of  ellagic  acid 
has  been  given.  This  latter  acid  is  extracted  from  the 
deposit  formed  at  the  bottom  of  the  vessels  by  treating 
it  first  with  boiling  water  which  dissolves  the  gallic 
acid,  and  then  with  a  dissolution  of  potash,  which  dis¬ 
solves  the  gallic  acid  in  the  state  of  ellagate  of  potash. 
The  alkaline  liquid,  when  evaporated,  deposits  the  latter 
salt  in  the  form  of  small  crystalline  spangles,  insoluble 


GALLIC  AND  ELLAGIC  ACIDS. 


57 


in  fresh  water,  but  dissolving  readily  in  alkaline  liquid. 
Acids  separate  ellagic  acid  in  the  form  of  a  slightly 
yellowish  powder. 

Ellagic  acid  is  insoluble  in  water,  alcohol,  and  ether, 
and  its  composition  corresponds  to  the  formula  C14H5O10. 
It  loses  two  equivalents  of  water  at  248°,  when  its  for¬ 
mula  becomes  C14H308.  The  formula  of  ellagic  acid  in 
combination  with  bases  being  C12H207,  that  of  the  dried 
acid  is,  therefore,  C14OcH7,HO,  and  that  of  the  hydrated 
acid  C14H207,H0  +  2HO. 

Ellagic  acid  is  said  to  be  the  chief  agent  that  gives 
the  bloom  to  the  tanned  hide.  It  will  interest  the 
reader  to  know  the  various  derivatives  of  tannic  acid. 
They  play  no  part  in  tanning,  but  they  are  curious  as  a 
scientific  fact. 

Tannic  acid  C1SHS012. 

Oxy tannic  acid  C15Hs014,  generated  by  the  combined 

action  of  potash  and  the  atmos¬ 
phere. 

il lelanotannic  acid  C14H609,  generated  by  the  joint  action 

of  potash,  air,  and  heat. 

Melanogallic  acid ,  metagallic  C12H303,  by  the  sudden  ac¬ 
tion  and  continuance  at  a  tempera¬ 
ture  of  480°. 

C7H305,  by  the  action  of  air  and  water 
or  the  action  of  heat,  water,  and 
sulphuric  acid. 

C7H204,  by  the  action  of  air  and 
water. 

C7H2()4,  by  the  joint  action  of  water, 
sulphuric  acid,  and  a  temperature 
of  285°. 

C6H303,  by  sublimation  of  galls  and 
of  gallic  acid  at  410°. 


Gallic  acid 

Ellagic  acid 
Paraellagic  acid 

Pyrogallic  acid 


58 


CHEMISTRY  OF  TANNING. 


CHAPTER  VI. 

EXTRACTIVE. 

The  term  extract  was  employed  by  apothecaries  to 
denote  that  portion  of  any  vegetable  substance  which 
had  been  dissolved  by  digesting  it  in  any  menstruum 
whatever,  and  which  had  afterwards  been  reduced  to  a 
thick  consistence  by  distilling  off  the  menstruum,  if 
valuable,  or  by  evaporating  it  away  if  not  worth  pre¬ 
serving.  So  that  originally  the  portions  of  plants  dis¬ 
solved  by  water,  alcohol,  wine,  acetic  acid,  carbonate  of 
potash,  etc.,  and  afterwards  inspissated,  were  called  ex¬ 
tracts.  This  is  the  meaning  which  the  word  bears  in 
the  Pharmacopee  Roycile  Galenique  et  Chymique  of  Char- 
ras,  published  in  Paris  in  1776.  Thus  the  extract  of 
opium  of  Charras  was  made  by  digesting  opium,  first  in 
water,  afterwards  in  alcohol,  till  everything  soluble  in 
these  menstrua  had  been  taken  up.  The  two  solutions 
were  mixed,  the  alcohol  distilled  off,  and  the  water 
evaporated  at  a  gentle  heat.  What  remained  was  called 
extract  of  opium.  In  process  of  time,  these  extracts 
were  divided  into  two  sets:  namely,  watery  and  spiritu¬ 
ous,  or  yummy  and  resinous,  according  as  the  menstruum 
employed  was  water  or  alcohol.  This  distinction  was 
attended  to  in  the  time  of  Neumann.  Afterwards  the 
term  extract  came  to  be  restricted  to  what  was  obtained 
from  vegetables,  by  macerating  them  in  water  and  evapo¬ 
rating  the  watery  liquid  to  dryness. 

The  extracts  obtained  in  this  way  were  generally 
considered  as  soaps,  till  Fourcroy  and  Vauquelin  pub¬ 
lished  some  observations  on  the  subject  in  1790.  Ac¬ 
cording  to  them,  extract  is  a  substance  at  first  soluble  in 
water ;  but  which,  when  the  solution  is  exposed  to  the 
air,  absorbs  the  oxygen  and  becomes  insoluble.  Chlo¬ 
rine  gas  speedily  converts  it  into  a  solid  yellow  sub¬ 
stance  insoluble  in  water  but  soluble  in  alcohol  and 
alkalies.  They  inform  us  that  they  examined  12  dif¬ 
ferent  extracts  and  found  the  same  characters  in  all. 


EXTRACTIVE. 


59 


In  the  year  1791,  they  published  an  elaborate  analysis 
of  the  cinchona  bark  of  St.  Domingo,  in  which  a  great 
many  experiments  on  extracts  are  stated ;  and  soon  after, 
Yauquelin  made  a  set  of  experiments  on  the  extractive 
principle  of  vegetables.  Fourcroy,  in  his  General  System 
of  Chemical  Knowledge ,  published  about  the  beginning  of 
the  present  century,  recapitulates  the  facts  ascertained 
by  Y auquelin  and  himself.  The  extracts  from  vegetables 
are  very  complex  in  their  nature,  but  they  all,  in  his 
opinion,  contain  a  peculiar  principle,  to  which  he  con¬ 
fined  the  term  of  extract.  According  to  him  it  possesses 
the  following  properties. 

It  is  at  first  soluble  in  water,  but  rapidly  absorbs  oxy¬ 
gen  from  the  air,  or  other  substances  capable  of  yielding 
it.  By  this  absorption  it  acquires  a  brown  color  and 
becomes  insoluble  in  water.  It  has  a  strong  affinity  for 
alumina,  and  is  taken  away,  and  the  liquid  discolored, 
when  alum  mixed  with  an  alkali  is  agitated  in  a  solution 
containing  the  extract. 

De  Saussure  afterwards  showed  that  the  substance 
called  extract  or  extractive  by  Fourcroy  and  Yauquelin 
did  not  combine  with  the  oxygen  which  was  absorbed, 
but  gave  out  hydrogen  to  it  so  as  to  convert  it  into 
water.  The  extractive,  therefore,  was  not  rendered 
insoluble  by  uniting  with  oxygen,  but  by  being  deprived 
of  hydrogen.  It  contains  a  greater  proportion  of  carbon 
than  it  did  when  soluble  in  water,  and  hence  doubtless 
the  reason  why  it  assumes  a  brown  color. 

Berzelius  has  distinguished  this  brown  extractive  by 
the  name  of  apotheme;  it  possesses  the  following  prop¬ 
erties  : — 

It  is  not  completely  insoluble  in  water,  communicating 
a  yellow  reddish-brown  or  red  color  to  that  liquid,  and 
is  again  deposited  when  the  liquid  is  evaporated.  But, 
it  is  dissolved  with  very  great  difficulty,  and  a  minute 
portion  of  it  communicates  a  great  deal  of  color  to  that 
liquid.  Boiling  water  dissolves  more  than  cold,  and  the 
excess  is  deposited  as  the  solution  cools.  It  is  much 
more  soluble  in  alcohol  than  in  water,  and  more  soluble 
in  hot  than  in  cold  alcohol. 


60 


CHEMISTRY  OF  TANNING. 


Its  best  solvent  is  caustic  potash,  which  dissolves  a 
great  quantity  of  it,  and  assumes  a  deep  brown  color. 
The  alkaline  carbonates  dissolve  it  also.  The  acids  pre¬ 
cipitate  it  from  these  solutions. 

The  apotheme,  thus  set  at  liberty,  combines  with  the 
excess  of  acid  employed  to  precipitate  it,  and  acquires 
the  property  of  reddening  litmus  paper.  It  has  a  strong 
tendency  to  combine  with  acid  bodies ;  this,  doubtless, 
alters  its  character.  But  it  is  very  probable  that  there 
are  various  species  of  apotheme,  differing  from  each 
other  according  to  the  plants  from  which  they  have 
been  obtained,  though  this  subject  has  not  hitherto  at¬ 
tracted  the  attention  of  modern  chemist.  We  need  a 
set  of  experiments  on  this  subject,  with  an  ultimate 
analysis  of  apotheme,  in  as  pure  a  state  as  possible,  and 
extracted  from  different  plants. 


SECTION  II. 

TANNING  MATERIALS. 

Substances  which  are  available  for  the  purpose  of 
tanning,  embrace  a  wide  range  of  the  juices,  barks, 
leaves,  roots,  fruits,  and  excrescences  of  trees ;  vegeta¬ 
bles  which  contain  tannin,  of  one  kind  or  another,  may 
be  taken  into  account.  In  looking  over  the  researches 
and  labors  of  chemists,  many  hundred  substances  which 
yield  tannin  have  been  discovered ;  but  practice,  or  the 
trade,  recognize  only  a  few  of  these ;  probably  owing 
to  the  quantity  which  can  be  annually  produced,  their 
yield  in  tannin,  or  because  they  offer  some  advantages, 
either  in  making  a  better  leather,  or  in  the  time  re¬ 
quired  to  effect  the  operation.  The  tannin  and  other 
distinct  principles  in  vegetable  growth  of  every  kind, 
are  derived  from  the  sap  or  soluble  matters  imbibed  by 
the  rootlets  from  the  soil  in  which  the  plant  exists,  and 
the  gases  absorbed  by  the  foliage.  In  many  plants 


TANNING  MATERIALS. 


61 


which  elaborate  tannin,  it  is  met  with  in  small  propor¬ 
tions,  owing,  perhaps,  to  its  being  only  a  secondary  and 
not  a  primary  secretion.  It  is  found  in  some  vegetables 
equally  in  all  parts,  whilst  in  others,  certain  parts  are 
richer  in  this  substance,  the  remaining  exhibiting  only 
slight  indications  of  its  presence.  The  particular  por¬ 
tions  of  plants  that  yield  the  greatest  amount  of  tannin 
are,  therefore,  preferred  in  making  leather. 

The  following  is  a  list  of  the  materials  which  contain 
tannin  in  the  largest  quantities,  and  which  may  be  em¬ 
ployed  in  the  manufacture  of  leather: — 

Inspissated  and  pre-  f  Kino. 

pared  Extracts.  (_  Catechu  or  Cutch. 

Vegetable  Excrescences.  Galls. 

of  the  different  hinds  of  willow, 
of  the  common  oak,  Turkey  oak,  evergreen 
oak,  and  other  varieties, 
of  the  common  heath,  and  other  varieties 
of  the  same  plant. 

Garden  artichoke. 

Sloe  tree. 

Spotted  hemlock. 

Bearherry. 

Several  varieties  of  black  and  green  tea. 
Sumach. 

Grape. 

Hydro-sapathum  and  wild  cornel. 

Hidls  of  the  fruit  of  the  ccesalpina  cori- 
aria,  or  divi-divi. 

Bulbs  of  the  savilla  maritima. 

Dried  acorn  hulls  of  the  prickly  copped 
oak. 

All  woods  of  trees,  the  barks  of  which 
yield  tannin,  also  afford  more  or  less 
of  this  substance;  they  are  scarcely 
employed. 

Leadwort. 

Malefern.  • 

Rhatcmy. 

Leopard's  bane. 

Marsh  rosemary. 

Birch,  chestnut,  horse-chestnut,  sassafras, 
larch ,  hazel,  beech,  Lombardy  poplar, 
blackthorn,  pomegranate,  ash,  elm,  cork 
tree ,  cinchona,  willow,  sycamore,  tulip 
tree,  vsattle,  oak,  sumach,  winter  bark. 


Tree  Leaves 


Seeds  and  Bulbs. 


Woods. 


Roots. 


Barks. 


62 


CHEMISTRY  OF  TANNING. 


It  will  not  be  uninteresting  to  state  briefly  some  of 
the  properties  of  the  substances  mentioned  in  the  fore¬ 
going  table,  with  respect  to  their  uses  for  tanning  pur¬ 
poses. 


CHAPTER  VII. 

TANNING  SAPS — TANNING  JUICES — KINO — CATECHU. 

TANNING  SAPS. 

It  is  the  general  opinion  of  physiologists,  that  plants 
receive  a  considerable  part  of  their  nourishment  by  the 
root ;  that  it  enters  into  them  in  a  liquid  state  and 
passes  up  in  proper  vessels  towards  the  leaves.  This 
liquid  is  distinguished  by  the  name  of  sap.  In  the 
spring,  when  the  buds  begin  to  expand  themselves  into 
leaves,  if  we  break  off  the  extremity  of  a  branch,  or 
cut  into  the  wood  of  a  tree,  this  sap  flows  out,  and  may 
be  obtained  in  considerable  quantities.  It  was  first  ex¬ 
amined  by  Dr.  Hales  ;  but  chemical  analysis  had  not 
made  sufficient  progress  in  his  time  to  enable  him  to 
ascertain  its  constituents.  Deyeux  and  Vauquelin 
have  more  recently  analyzed  the  sap  of  different  trees. 
To  them  we  are  indebted  for  most  of  the  facts  known 
respecting  this  liquid.  A  few  additional  ones  have 
been  ascertained  by  John. 

The  sap  in  all  the  vegetables  hitherto  examined  is 
nearly  as  liquid  as  water.  It  always  contains  an  acid, 
sometimes  free,  but  more  commonly  combined  with  lime 
and  potash.  Various  vegetable  principles  are  also  pre¬ 
sent  ;  of  these  sugar  is  the  most  remarkable,  and  muci¬ 
lage.  Sometimes  albumen  and  gluten,  and  sometimes 
tannin,  can  be  detected.  When  left  to  itself,  the  sap 
soon  effervesces  and  becomes  sour,  or  even  vinous  when 
the  proportion  of  sugar  is  considerable. 

Hitherto,  the  sap  of  a  few  species  of  trees  only  has 
been  examined.  We  are  not  in  possession  of  any 
means  of  collecting  the  sap  of  the  inferior  orders  of 
plants.  The  expressed  juices  of  a  considerable  number 


TANNING  SAPS. 


63 


of  vegetables,  indeed,  have  been  prepared  for  medicinal 
purposes,  but  those  are  not  sap,  but  a  collection  of  all 
the  liquid  substances  which  the  plant  contains.  At 
present,  then,  it  is  not  possible  to  present  a  general  view 
of  the  properties  of  sap.  The  following  are  the  par¬ 
ticular  species  in  which  tannin  has  been  met  most 
abundantly. 


Sap  of  the  Beech  Tree  (Faff us  sylvaticus). 

Vauquelin  collected  two  different  specimens  of  this 
sap,  the  first  in  the  end  of  March,  the  second  about  the 
end  of  April.  It  has  a  reddish-brown  color,  and  a  taste 
similar  to  the  infusion  of  tan.  It  slightly  reddens  vege¬ 
table  blues.  Baryta,  ammonia,  carbonate  of  potash,  and 
oxalate  of  ammonia,  occasion  precipitates  in  it ;  chlorine 
throws  down  yellow  flakes,  sulphuric  acid  blackens  it, 
and  disengages  the  odor  of  acetic  acid.  Sulphate  of  iron 
strikes  a  black,  and  glue  throws  down  a  copious  whitish 
precipitate.  When  gently  evaporated  to  dryness,  it 
leaves  a  brown  extract  amounting  to  about  ^-g  of  its 
weight,  ductile  while  hot,  but  brittle  when  cold,  and 
having  the  smell  and  somewhat  of  the  taste  of  newly 
baked  bread.  It  absorbs  moisture  from  the  atmosphere, 
and  increases  in  weight  about  Lime  disengages  am¬ 
monia,  and  sulphuric  acid,  acetic  acid  from  this  extract. 
Alcohol  dissolves  only  a  small  part  of  it.  This  sap 
contains  the  following  ingredients : — 


Water , 

Acetate  of  lime , 
Acetate  of  potash. 
Acetate  of  alumina. 


Acetic  acid , 

Gallic  acid, 

Tannin, 

Mucous  and  extractive  matter. 


It  contains,  besides,  a  coloring  matter,  which  may  be  fixed 
on  cotton  and  linen  by  means  of  alum,  and  dyes  them 
of  a  fine  solid  reddish-brown  color. 

The  sap  of  the  oak  contains  tannin ;  the  sap  of  the 
maple  is  composed  as  follows : — 


Tannin,  Common  salt, 

.  Gallic  acid.  Salts  of  lime,  potash,  and  alumina. 
Acetic  acid. 


64 


CHEMISTRY  OF  TANNING. 


TANNING  JUICES. 

The  sap  passes  from  the  root  through  peculiar  vessels 
to  the  leaves,  where  it  is  altered  by  a  process  similar  to 
that  of  digestion  in  animals,  and  formed  into  all  the 
liquid  substances  requisite  for  the  purposes  of  the  plant. 
These  liquids  flow  from  the  leaves  towards  the  root  in 
appropriate  vessels,  and  have  received  the  name  of  the 
peculiar  juices  of  vegetables.  They  differ  very  considera¬ 
bly  from  each  other  in  different  plants.  They  have  all 
a  certain  degree  of  consistency,  and  always  contain 
much  more  vegetable  matter  than  the  sap.  In  the 
present  state  of  organic  chemistry,  accurate  details  of 
their  properties  cannot  be  attempted  ;  indeed,  it  is  often 
difficult  to  procure  them  from  any  plant,  unmixed  with 
the  sap.  They  sometimes  exude  spontaneously,  and 
may  always  be  procured  in  smaller  or  greater  quantity, 
by  incisions  through  the  bark  of  the  plant  containing 
them.  Many  vegetable  juices  contain  tannin,  and  we 
give  below  the  three  most  generally  employed. 

Kino. 

For  a  long  time  the  origin  of  kino  was  unknown,  but 
it  has  recently  been  ascertained  to  be  the  product  of  a 
lofty  tree  growing  upon  the  mountains  of  the  Malabar 
coast  of  Hindoostan,  named  Pterocarpus  Marsupium , 
belonging  to  the  natural  order  of  Fabacece. 

Kino  is  the  juice  of  the  tree  obtained  by  making 
longitudinal  incisions  in  the  bark  ;  it  flows  abundantly, 
and  is  of  a  red  color,  and  by  drying  it  in  the  sun,  it 
cracks  into  irregular  angular  masses,  which  are  placed 
in  wooden  boxes  for  exportation.  It  sometimes  comes 
to  this  country  from  the  East  Indies,  but  more  generally 
from  England.  East  Indian  kino  is  usually  in  small, 
irregular,  angular,  shining  fragments,  in  size  between 
a  pin’s  head  and  a  pea,  of  a  dark  reddish-brown  or 
blackish  color,  opaque,  very  brittle,  easily  pulverizable, 
and  affording  a  reddish  powder,  much  lighter  colored 
than  the  drug  in  its  aggregate  state,  and  which  becomes 
brownish  on  being  kept  for  some  time.  It  is  inodorous 


TANNING  SAPS. 


65 


and  of  an  intensely  pure  astringent  taste.  Boiling 
water  dissolves  a  large  proportion  of  it,  forming,  when 
cold,  a  permanent  intense  blood-red  solution ;  and  which 
yields  with  sesquichloride  of  iron  a  dark  green,  coarsely 
flocculent  precipitate,  which  is  so  abundant  as  to  render 
the  whole  liquid  pulpy.  Acetate  of  lead  affords  a  gray 
precipitate,  and  tartar  emetic  a  gradually  formed  lake- 
red  muddy  jelly.  Clear  water  forms  with  it  a  clear 
sherry  red  solution,  leaving  a  crumbly,  grayish-red  resi¬ 
duum  ;  alcohol  dissolves  about  I  of  it,  and  forms  a  deep 
brownish-red  tincture  which  is  not  disturbed  by  water. 
It  contains  75  per  cent,  of  tannin,  and  a  peculiar  ex¬ 
tractive,  24  of  red  gum,  and  one  of  insoluble  matter. 
Its  aqueous  solution  precipitates  gelatin,  the  soluble  salts 
of  iron,  silver,  lead,  antimony,  bichloride  of  mercury, 
and  sulphuric,  nitric,  and  muriatic  acids. 

African  kino  is  rarely  seen  in  commerce ;  it  exudes 
from  the  Pterocarpus  erinaceus.  The  dha  tree  kino  is 
the  product  of  the  butea  frondosa,  an  East  India  tree; 
it  contains  from  70  to  90  per  cent,  of  tannin.  It  is 
much  used  in  India.  The  Botany  Bay  kino  is  the  con¬ 
crete  juice  of  the  Eucalyptus  resinifera ,  or  brown  gum- 
tree  of  New  Holland.  It  is  easily  powdered;  the 
powder  has  an  amber  color ;  dissolves  slowly  in  cold 
water,  and  rapidly  in  boiling  water,  forming  a  deep 
cherry  red  solution,  which  on  cooling  precipitates  in  a 
copious  brick  colored  deposit,  if  the  solution  be  made 
with  1  part  of  kino  in  25  of  water. 

Jamaica  Kino.  Product  of  the  coccoloba  tivifera, 
growing  in  the  West  Indies.  It  contains  41  per  cent, 
of  tannin. 

South  American,  Columbia  or  Caraccas  Kino,  is 
derived  from  the  coccoloba  uvifera ,  which  grows  upon 
the  continent  as  well  as  in  the  islands.  It  is  imported 
*  in  heavy  mass,  and  closely  resembles  the  Jamaica  kino 
in  color,  lustre,  taste,  and  other  properties.  Cold  water 
dissolves  89  per  cent,  and  alcohol  94  per  cent. 


5 


66 


CHEMISTRY  OF  TANNING. 


Catechu. 


Catechu  is  another  of  the  same  class  as  the  preceding, 
and  forms  a  most  useful  article  for  the  tanner.  There 
are  several  varieties,  which  are  distinguished  by  various 
names,  such  as  cutch,  terra-japonica ,  and  gambir.  For¬ 
merly  this  extract,  from  its  brownish-red  color,  was  sup¬ 
posed  to  be  a  kind  of  earth,  hence  the  title  terra  given 
to  it.  Catechu  is  extracted  from  the  acacia  catechu,  a 
tree  which  grows  to  the  height  of  20  or  30  feet,  and 
abounds  in  the  forests  from  latitude  26°  to  30°,  known 
as  the  Bornese  territory  on  the  Malabar  coast,  and  called 
Caucan.  The  heart  and  bark  of  the  wood  are  boiled  in 
water,  and  the  solution  evaporated,  which  leaves  the 
astringent  extract  known  as  Caucan  catechu.  Accord¬ 
ing  to  Nees  Von  Esenbeck  most  of  the  catechu  ex¬ 
ported  from  Bombay  is  prepared  from  the  acacia  catechu, 
whilst  that  brought  from  Bengal  is  derived  from  the 
uncaria  gambir ,  a  shrub  cultivated  in  the  countries  lying 
on  both  sides  of  the  shores  of  Malacca.  It  is  obtained 
by  boiling  the  wood,  bark,  and  leaves  of  this  shrub 
together  with  the  inspissated  juice  in  water,  and  evapo¬ 
rating,  then  adding  a  little  sago  to  give  it  consistency ; 
it  is  finally  exsiccated  in  the  sun,  and  then  cut  into 
square  or  circular  cakes  to  suit  the  purchaser.  Bombay 
catechu,  which  is  the  richest  in  tannin,  is  of  a  dark 
brownish-red  hue,  both  externally  and  internally,  and 
possesses  a  specific  gravity  of  1.38.  Davy  examined 
the  Caucan  catechu,  and  found  it  to  be  1.39;  he  also 
found  in  200  parts  of  this  as  well  as  of  the  Bengal  cate¬ 
chu,  and  known  by  the  title  Pegu ,  from  the  province 
of  Bengal,  where  it  is  prepared,  the  following  con¬ 
stituents  : — 


Caucan  or  Bombay.  Pegu  or  Bengal. 


Tannin 
Extractive 
Mucilage 
Earthy  residue 


54.50  48.50 

34.00  36.50 

6.50  8.00 

5.00  7.00 


100.00  100.00 


TANNING  SAPS. 


67 


Cooper  found  in  Cutch ,  which  is  a  commercial  name 
for  catechu — 


Water  .  .  .  .  .  .  .  12  8 

Tannin  .  .  .  .  .  .  .  47.7 

Extractive  matter  .  .  .  .  .  9.2 

Gummy  “  .  .  .  .  .  136 

Resinous  “  .  .  .  .  .  6.8 

Insoluble  residue  .  .  .  .  .  .  9.9 


100.0 

The  genuine  catechu,  of  whatever  variety,  csntains 
on  an  average  about  half  its  weight  of  tannin,  and  its 
efficacy  in  converting  skin  into  leather  has  been  esti¬ 
mated  as  being  five  times  greater  than  the  best  oak 
bark ;  but  this  seems  exaggerated.  Besides  the  real 
tannin  the  extractive  matter  contained  in  it  is  another 
definite  substance,  which  is  called  catechin ,  or  catechuic 
acid ,  and  which  doubtless  plays  a  part  in  the  process  of 
tanning.  It  possesses  the  property  of  coloring  the 
leather  deeply.  This  body  differs  from  the  tannin  in 
being  insoluble  in  cold  water,  although  a  solution  of  the 
tannin  of  catechu  takes  up  a  small  quantity  of  it.  The 
varieties  of  catechu  of  commerce  are — 

1.  Cake  Catechu ,  from  its  being  in  circular  cakes. 
Their  color  varies  from  a  light  brown  to  a  black,  and 
their  weight  from  several  ounces  to  two  pounds. 

2.  Pegu  Catechu. — As  already  stated,  this  variety  ob¬ 
tains  its  name  from  the  province  where  it  is  prepared. 
It  is  generally  imported  in  masses  of  a  hundred  pounds 
weight,  but  as  seen  in  the  shops  it  presents  the  appear¬ 
ance  of  angular,  irregular  fragments,  in  double  layers 
with  leaves  between.  It  has  a  compact  shining  fracture 
and  a  deep  brown  color. 

6.  Bengal  Catechu  is  manufactured  into  rectangular 
cakes,  but  in  the  course  of  transit  they  become  reduced 
to  fragments.  Externally  it  has  a  rusty-brown  color,  and 
internally  the  shades  vary  from  a  brownish-gray  to  dark 
brown. 

4.  Bombay  Catechu. — This  variety  occurs  in  globular 
lumps  of  the  size  of  an  orange  flattened,  and  two  pieces 


68 


CHEMISTRY  OF  TANNING. 


generally  adhering  together.  In  color  it  resembles  that 
brought  from  Bengal. 

5.  Gambir. — It  is  stated  by  M’Culloch  that  no  less 
than  4600  tons  of  catechu  under  the  name  of  gambir  are 
produced  annually  by  the  Chinese  settlers  in  Bio.  It 
takes  the  name  from  the  shrub  which  is  its  source,  the 
uncaria  or  nauclea  gambir.  It  has  a  deep  yellow  or  red¬ 
dish-brown  color  on  the  outside,  but  within  it  is  paler, 
and  presents  a  dull  earthy  fracture.  It  comes  to  this 
country  in  solid  masses  of  about  a  cubic  inch  in  size. 
EsenUeck,  who  examined  this  variety,  states  that  it 
yields  from  36  to  40  per  cent,  of  tannin.  Boiling  water 
entirely  dissolves  it. 

6.  Areca  Catechu. — The  nut  of  an  Indian  palm  known 
by  this  title  affords  this  kind  of  astringent  substances. 
These  fruits  are  macerated  with  water,  and  the  decoc¬ 
tion  is  made,  when  a  better  sort  of  catechu  results, 
known  by  the  term  kassa,  and  the  semi-exhausted  resi¬ 
due,  upon  further  treating  it  with  water,  affords  a  solid 
extract,  which  is  distinguished  as  caury.  The  former  is 
of  a  black  color  and  intermixed  with  husks,  and  the 
latter  of  a  yellowish-brown  with  an  earthy  fracture. 
The  caury  is,  of  course,  inferior  to  the  extract  known  as 
kassu. 

With  regard  to  the  application  of  catechu  to  the 
manufacture  of  leather,  the  natives  of  India  have  long 
practised  it ;  but  its  introduction  into  the  trade  in  this 
country  for  a  similar  purpose  is  of  recent  date.  Its 
richness  in  the  tanning  agent  causes  its  action  to  be  very 
rapid  in  producing  a  gelatino-tannate  of  the  substance 
of  the  » skin,  or,  in  other  words,  of  making  leather. 
The  qualities  of  the  article  manufactured  from  it  are 
not,  however,  so  satisfactory  as  the  rapidity  of  its  effects, 
either  to  the  tanner  or  the  public ;  for  the  leather  is 
very  permeable  to  water,  light  and  spongy,  hard,  and  of 
a  dark-reddish  fawn  color.  The  characteristic  deposit 
from  oak  bark,  and  a  few  other  tanning  agents  known 
as  bloom ,  is  not  produced  by  catechu,  and  this  want  is  a 
material  objection  to  its  use,  as  the  existence  of  bloom 
upon  leather  is  considered  as  a  kind  of  guarantee  of  its 


EXCRESCENCES  CONTAINING  TANNIN. 


69 


goodness.  One  pound  of  catechu  of  good  quality  is 
capable  of  producing  one  pound  of  leather,  and  conse¬ 
quently,  in  tanning  power  is  equivalent  to  five  of  oak 
bark,  or  thereabouts,  as  already  stated. 


CHAPTER  VIII. 

EXCRESCENCES  CONTAINING  TANNIN. 

NUTGALLS. 

There  is  no  other  natural  product  that  affords  so 
much  tannin  as  those  round,  hard,  woody  excrescences 
known  as  galls.  Formerly  it  was  supposed  that  these 
were  a  kind  of  fruit,  but  naturalists  and  physiologists 
have  ascertained  that  is  not  the  case,  but  that  they  are 
excrescences  or  tumors,  which  form  on  the  branches  of 
different  trees  and  vegetables,  owing  to  the  puncture  of 
certain  insects,  for  the  purpose  of  depositing  their  eggs. 
The  tree  which  affords  those  galls  that  are  commonly 
known  as  nut  galls ,  is  a  stunted  species  of  oak — quercus 
infectoria — which  is  generally  found  throughout  Asia 
Minor.  It  grows  to  the  height  of  four  to  six  feet,  has  a 
crooked  stem,  and  yields  an  acorn  two  or  three  times 
larger  than  its  cup.  The  gall  flies,  which  occasion  the 
gall,  belong  to  the  g^nus  cynips,  and,  from  different 
accounts,  there  are  several  species ;  that  which  is  con¬ 
cerned  in  producing  the  officinal  galls,  is  the  cynips 
gallce  tinctorice .  The  female  insect  of  this  variety,  by 
means  of  an  appropriate  apparatus,  perforates  the  corti¬ 
cal  part  of  the  plant,  and  in  the  wound  deposits  her 
eggs,  together  with  an  acid  liquor.  In  two  or  three 
days  the  part  is,  as  it  were,  inflamed,  and  a  swelling  ap¬ 
pears,  and  continues  to  increase  till  it  results  in  a  gall. 
The  eggs  which  are  inclosed  in  this  excrescence  are 
hatched,  and  in  due  time  the  young  larvae  appear,  and 
develop  themselves,  being  supported  by  the  juices  of 
the  plant  till  they  become  a  perfect  insect,  when  they 
perforate  the  galls  and  escape.  When  this  happens,  the 
excrescence  loses  much  of  its  astringent  principle,  and 


70 


CHEMISTRY  OF  TANNING. 


becomes  lighter;  but  if  gathered  or  harvested  before  the 
entombed  insect  is  completely  developed,  the  nuts  are 
not  only  heavier,  but  are  richer  in  tannin  and  command 
a  better  price  in  the  market.  Galls  gathered  before  the 
escape  of  the  insect,  have  a  black  or  bluish  shade;  but 
when  the  insect  has  left,  their  color  is  paler,  and  they 
generally  attain  to  a  larger  size.  To  prevent  this  occur¬ 
rence,  great  care  is  taken  to  harvest  the  galls  before  the 
insect  attains  its  full  growth,  and  eats  its  way  through, 
leaving  them,  however,  on  the  trees  till  they  have 
acquired  their  greatest  growth.  In  some  parts,  the 
governor,  or  aga  of  the  district,  levies  a  tax  on  the  pro¬ 
duce;  and  being  thus  interested  in  the  success  of  the 
crop,  he  causes  the  cultivator  to  traverse  frequently  the 
hills  and  mountains,  to  report  upon  the  advanced  state 
of  the  galls,  and  whenever  the  proper  growth  has  been 
attained,  they  are  immediately  collected.  The  selections 
thus  made  are  known  in  the  market  as  green-galls ,  and 
come  to  this  country  from  Aleppo,  Smyrna,  and  the 
interior  of  Asia  Minor.  Those  which  escape  harvesting 
before  the  entombed  insect  has  attained  its  full  growth 
or  emerged,  are  known  as  white  galls ,  and  are  imported 
from  the  same  place.  Another  kind  of  gall,  produced 
upon  the  oaks  growing  in  many  departments  of  France, 
are  nearly  equal  in  size  to  the  Asiatic  green  galls,  but 
they  are  rounder,  and  possess  q,  smooth  and  in  some 
instances  a  polished  surface.  They  have  a  brownish 
color,  and  rank,  in  their  content  of  tannin,  intermediate 
between  the  green  and  white  Aleppo  galls.  A  variety 
originating  from  the  puncture  of  an  insect  allied  to  the 
aphis  on  the  branches  and  shoots  of  the  dystylium  race- 
mosum,  comes  from  Japan.  They  are  of  an  irregular 
shape,  having  in  some  instances  both  ends  small,  whilst 
the  middle  is  much  thicker,  but  more  generally  the 
stem  end  is  the  least  and  the  more  swollen  part  is  nearer 
the  other.  Hence  they  are  called  apple-galls. 

Annexed  are  the  analyses  of  samples  of  Aleppo  and 
Chinese  galls  by  Guibourt  and  Davy: — 


LEAVES,  TEA,  FLOWERS  AND  FRUITS.  71 

Aleppo  galls. 

, - ■ - >  Chinese  galls. 


Guibourt. 

Davy. 

By  Bley. 

Tannin  .... 

65.0 

26.0 

69.00 

Gallic  acid 

2.0 

6.2 

fat  1 

alb’en  > 

4.00 

Elagic  acid 

Brown  extractive 

2  0 

2.5 

— 

-  3.00 

resin 

Starch  .... 

2.0 

) 

cellular] 

Gum  .... 

2  5 

Y  2-4 

16.00 

Sugar  .... 

1.3 

matter  j 

Chlorophvl  and  vol.  oil  . 

0.7 

— 

— 

Woody  fibre  . 

10.5 

|  65.4 

— 

Water  .... 

11.5 

8.00 

100.0 

100.0 

100.00 

CHAPTER  IX. 

LEAVES— TEA— FLOWERS  AND  FRUITS— SEEDS  AND  BULBS. 

LEAVES. 

Of  the  foliages  of  trees  containing  tannin,  very  few, 
if  any,  are  now  employed  in  the  manufacture  of  leather. 
The  leaves  of  the  heath  were  once  extensively  used,  but 
this  material  has  long  since  been  abandoned,  preference 
being  given  to  oak  barks  and  other  substances  of  native 
and  foreign  growth. 

List  of  Tanning  Leaves. 

1.  Leaves  of  the  different  species  of  willow:  common 
white  willow  [salix  alba ),  water  willow  [salix  caprea ), 
cracking  willow  {salix  fragilis),  red  willow  {salix  pent  an- 
dria ),  Howny-mount  willow  {salix  arenaria ),  weeping 
willow  ( salix  babylonica).  Pyrenean  willow  ( salix  aurige- 
rana ,  S.  grandifolia ,  S.  pyrena'ica),  black  willow  ( S . 
nigricana ),  sharp  leaved  willow  {S.  cxsia,  S.  lanceolata ), 
yellow  willow  {S.  vitellina ),  osier  willow  {S.  incana ,  S. 
viminalis ). 

2.  Leaves  of  the  service  tree  ( sorbus  domestica ),  and 
mountain  ash  (S.  aucuparid). 

3.  Of  the  pomegranate  (punica  granatum). 


72 


CHEMISTRY  OF  TANNING. 


4.  Of  the  beech-tree  ( fagus  syloatica),  chestnut  tree 
(S.  castanea). 

5.  Olive  tree  ( olea  Europce). 

6.  Of  the  common  medlar  ( mespilus  gcrmanica). 

7.  Of  the  common  dogwood  ( cornus  mas). 

8.  Of  the  hazel-nut  tree  ( corylus  arellana). 

9.  Of  the  common  birch  ( betula  alnus ,  B.  alba). 

10.  Of  the  red  rose  ( [rosa  gallica),  evergreen  rose  ( rosa 
sempervirens). 

11.  Of  the  common  ramble  (rubus  fruticosus),  dew¬ 
berry  (P.  ccesius),  the  cloud  berry  (R.  chamcemorus )  con¬ 
tains  7.3  of  tannin. 

12.  Of  the  yellow-rooted  water  dock  {rumex  aquaticus ). 

13.  Of  the  rosemary  ( rosamarinus  officinalis). 

14.  Of  the  common  European  oak  ( quercus  robur), 
Turkey  oak  ( Q .  cerris),  sessile-flowered  oak  (Q.  sessi- 
flora),  hoary  oak  (Q.  toza ),  Apennine  oak  (Q.  apennina ), 
evergreen  oak  (Q.  ilix). 

15.  Nearly  all  the  cist  us  family. 

16.  Of  the  common  heath  ( erica  vulgaris ),  fine  leaved 
heath  (erica  an  era),  cross-leaved  heath  (E.  tetralix). 

17.  Of  the  French  tamarisk  ( tamarix  gallica),  African 
and  German  tamarisk  (T.  Africana  and  Germanica). 

18.  Of  the  garden  artichoke  (cynara  scolynus ),  of  the 
twigs  and  leaves  of  the  cynara  cardunculus,  cardom. 

19.  Of  the  sloe  tree  ( prunus  spinosa ),  common  plum 
(P.  domestica ),  briancon  apricot  (P.  brigantiaca ),  common 
apricot  (P.  armeniaca) ,  sweet  almond  (amygdalus  com¬ 
munis),  common  peach  (A.  persica),  common  cherry  (P. 
cerasus) . 

20.  Of  the  spotted  hemlock  ( conium  maculatum). 

21.  Of  the  horse-chestnut  ( cesculus  hippo  cast  anuni). 

22.  Of  the  crowfoot  leaved  cranesbill  (geranium  pra- 
tense). 

23.  Of  the  common  cenothera,  or  evening  primrose 
( oenothera  biennis). 

24.  Of  the  lime-tree  (tilia  europcea). 

25.  Of  the  bearberry  ( arbutus  uva  ursi). 


LEAVES,  TEA,  FLOWERS  AND  FRUITS. 


73 


TEA. 

The  tea  plant  is  a  shrub  or  small  tree,  which  in  a  state 
of  nature  may  attain  a  height  of  twenty-five  to  thirty 
feet,  but  which,  when  cultivated,  seldom  exceds  six  or 
seven.  The  tea  plant  is  a  native  of  China  and  Japan  ; 
it  is  an  evergreen  shrub  from  four  to  eight  feet  high. 
It  is  divided  into  black  and  green  teas.  The  green  tea 
is  characterized  by  a  dark  green  color,' sometimes  inclin¬ 
ing  more  or  less  to  blue  or  brown.  It  has  a  peculiar, 
refreshing,  somewhat  aromatic  odor,  and  an  astringent 
slightly  pungent  and  agreeable  bitterish  taste.  Its  infu¬ 
sion  is  of  a  pale  greenish  yellow  color,  with  the  taste  and 
odor  of  the  leaves.  Black  tea"! s  distinguished  by  a  dark 
brown  color,  usually  less  firmly  rolled,  and  lighter  than 
the  green.  Its  odor  is  fainter  and  of  a  somewhat  differ¬ 
ent  character,  though  still  fragrant.  Its  taste  is  astrin¬ 
gent  and  bitterish,  less  pungent  and  less  agreeable  than 
the  green. 

The  composition  of  tea  is  shown  by  C.  J.  Mudler’s 
analysis : — 


Volatile  oil  . 

Geeen. 

0  79 

Black. 

0.60 

Chlorophylle  . 

2  22 

1.84 

Wax 

0.28, 

- - 

Resin  . 

2.22 

3.60 

Gum 

8.56 

7  28 

Tannin  . 

17.80 

12.88 

Thein 

0.43 

0.46 

Extractive 

22.80 

19.88 

Apotheme 

.  traces 

1.48 

Muriatic  extract 

23.60 

19.12 

Albumen 

3.00 

2.80 

Lignin  . 

17.68 

28.32 

Salts 

5.56 

5.24 

104.94 

Frank  found  the  tea  thus  formed: — 

103.50 

Tannin  . 

Gkeen. 

34.6 

Black. 

40.6 

Gum 

5.9 

6.3 

Ligneous  fibre 

. 

51.2 

44.8 

Gluten  . 

# 

5.7 

6.3 

Vol.  matter  and  loss 

2.5 

2.0 

100.0 

100.0 

74 


CHEMISTRY  OF  TANNING. 


FLOWERS  AND  FRUITS. 

Valonia. 

Hitherto  flowers  and  flower  tops,  though  containing 
tannin,  have  not  been  used  in  the  preparation  of  leather 
on  the  large  scale.  The  same  might  be  said  of  fruits 
with  the  exception  of  the  acorn-cups  of  the  quercus 
agilops,  prickly  cupped  oak,  a  tree  which  grows  in  abun¬ 
dance  in  the  Morea  and  the  adjacent  countries.  In 
commerce  they  pass  under  the  name  of  valonia,  and  are 
imported  from  Turkey,  Greece,  Italy,  and  India.  When 
the  fruit  is  gathered  it  is  conveyed  to  the  nearest  port 
to  be  shipped,  then  it  is  .stored  in  a  warehouse  during 
several  months,  being  laid  out  in  beds  of  three  to  five 
feet  in  thickness,,  A  slight  heating  or  fermentation  sets 
in  during  the  above  period,  and  as  the  moisture  escapes 
the  long  spreading  scales,  which  hitherto  confined  the 
acorn,  become  contracted  and  allow  the  latter  to  fall 
out  from  the  cup.  After  being  well  dried  the  whole  is 
picked,  and  the  acorn,  which  contains  no  tannin,  and 
the  damaged  cups  are  separated  from  those  of  the  latter 
that  are  dry  and  good.  The  cup  of  this  acorn,  so  long 
as  kept  dry,  retains  a  bright  drab  color ;  but  when  ex¬ 
posed  to  moisture,  it  loses  this  appearance  and  turns 
black,  losing  by  the  change  its  tanning  properties. 
Doubtless  to  the  long  exposure  of  the  upper  cups  to  the 
disengaged  vapors  from  the  bed,  is  owing  their  being 
invariably  more  or  less  damaged.  Ordinary  or  common 
valonia,  the  cups  of  which  average  about  2  inches  in 
diameter,  differs  from  that  kind  known  as  carnata  or 
carncetena  valonia.  which  are  only  about  the  size  of  a 
large  cherry ;  the  latter  is  said  to  be  the  fruit  of  a 
smaller  species  of  quercus  than  that  which  affords  the 
common  valonia.  It  is  in  greater  demand  for  silk 
dyeing  than  tanning. 

Leather  prepared  by  valonia  is  said  to  be  harder  and 
less  permeable  to  water  than  that  made  with  oak  bark ; 
and  besides  it  presents  the  advantage  of  readily  de¬ 
positing  a  rich  bloom  upon  the  leather,  a  characteristic 
much  sought  by  the  traders  in  this  article.  Not  less 


LEAVES,  TEA,  FLOWERS  AND  FRUITS. 


75 


than  10,000  to  12,000  tons  of  this  tanning  agent  are 
annually  used  in  England,  and  it  is  stated  that  two 
pounds  of  good  average  quality  are  sufficient  for  making 
one  pound  of  leather.  Its  price  varies  from  $50  to 
$100  per  ton.  Myrobalans,  the  dried  fruit  of  various 
species  of  terminalia ,  is  extensively  employed  in  tanning 
and  dyeing  factories.  There  are  several  kinds,  all  of 
which  come,  however,  from  the  East  Indies  through 
Calcutta  and  other  ports.  This  sort  of  fruit,  when  ripe, 
is  pear-shaped,  deeply  wrinkled,  of  brownish-yellow  hue, 
and  weighing  from  70  to  100  grains.  The  whole  of  the 
astringent  matter  which  it  yields  is  contained  in  the 
husk,  which  is  easily  separated  from  the  unclosed  nut 
by  bruising  the  whole.  Besides  the  tannin,  a  yellow 
coloring  matter  with  mucilage  and  other  principles  is 
extracted.  This  tannin  differs  slightly  from  that  found 
in  nutgalls. 

Divi-Divi  is  an  article  which  has  acquired,  within  a 
comparatively  modern  date,  an  interest  with  tanners  and 
commercial  men.  It  may  be  classed  with  the  foregoing, 
since  it  consists  of  the  dried  pods  of  a  leguminous 
shrub — Ccesalpina  coriaria ,  which  is  indigenous  to  South 
America,  and  grows  to  the  height  of  twenty  and  even 
thirty  feet.  The  pods  are  about  3  inches  long,  of 
dark  brown  color,  and  curled  up  as  if  they  had  been 
submitted  to  a  high  temperature  during  desiccation — 
the  whole  of  the  tannin  is  concentrated  in  the  rind  of 
the  pod,  immediately  beneath  the  epidermis,  and  has 
consequently  a  very  astringent  taste,  but  the  inner  por¬ 
tion  that  includes  the  seed  is  very  insipid.  Besides 
tannin,  it  yields  coloring  matter,  and  a  mucilaginous 
substance  which  interferes  with  its  application  in  dyeing 
and  printing.  The  leather  prepared  with  divi-divi  is 
very  porous,  and  tinged  brown  or  brownish  red,  accord¬ 
ing  to  the  density  of  the  ooze,  time  allowed,  and  state 
of  exposure  to  the  air.  Its  formation  is  attributed  to  a 
fermentative  change  induced  by  some  of  the  extractive 
matter ;  this  change  occurs  as  well  in  cold  as  in  warm 
weather,  but  more  frequently  in  the  latter.  During  the 
reaction  a  reddish  matter  deposits  upon  the  leather  in 


76 


CHEMISTRY  OF  TANNING. 


course  of  preparation,  and  on  the  side  of  the  pit.  By 
preventing  exudation  of  some  of  the  principles  present, 
through  the  exclusion  of  atmospheric  air,  none  of  the 
fore-mentioned  substances  appear,  and  the  leather  re¬ 
tains  the  natural  color.  A  solution  or  extract  of  divi- 
divi  readily  affords  a  deposit  of  bloom  to  leather.  Sten- 
house  has  shown  that  the  tanning  matter  of  divi-divi, 
though  similar  to  that  contained  in  galls,  inasmuch  as 
it  exerts  a  like  reaction  on  solutions  of  sesquisalts  of 
iron,  is,  nevertheless,  different  from  the  latter,  since  it 
produces  no  pyrogallic  acid  when  submitted  to  dry 
distillation. 

Of  Tanning  Flowers  and  Flower  Tops. 

Wild  tansy  ( potentilla  anserina ). 

Agrimony  ( agrimonia  eupatoria). 

Snakeweed  ( polygonum  bistorta). 

Malefern  (jilix  mas). 

Wood  strawberry  (frag  aria  vesca ). 

Drop  wort  ( spiraea  flipendula). 

St.  John’s  wort  ( liypericum perforatum). 

Common  cotton  rose  ( silago  germanica). 

Greater  and  lesser  periwinkle  ( vinca ,  major  and  minor). 

Spotted  persicaria  ( polygonum  persicaria). 

Plantain  ( plantago  major). 

Ladies’  mantle  ( alchemilla  vulgaris). 

Everlasting  ( graphalium  dioicum). 

Marsh  horse-tail  ( equisetum  palustre). 

Common  burnet  ( poterium  sanguisorba). 

Lungwort  ( lichen  pulmonarius). 

Cinquefoil  ( potentilla  reptans). 

Meadow  sweet  ( sporcea  ulmaria). 

Wood  cranesbill  (geranium  grandiflorum). 

lied  rose  (rosa  gallica). 

Hop  ( humulus  lupulus)  contains  more  than.  0.4  of 
tannin  and  gallic  acid. 

Clove  tree  ( Eugenics  cargophgllata)  contains  .13  of  a 
peculiar  tannin. 

Common  avens  ( geum  urbanum)  is  an  European  plant. 


WOODS — ROOTS — BARKS. 


77 


Its  root  is  very  rich  in  tannin,  and  contains,  according 
to  Tromsdorff — 


Volatile  oil  ( heavier  than  water)  . 

0.038 

Resin  ...... 

3.998 

Tannin  ( soluble  in  alcohol  and  ether)  . 

40.984 

Adraganthine  ..... 

9.196 

Gummy  matter  ..... 

.  15.193 

Woody  fibre  ..... 

.  29.99k 

100.000 

The  water  avens  ( geum  rivale )  which  grows  on  this 
continent  from  Canada  to  Pennsylvania,  likewise  pos¬ 
sesses  tanning  properties. 

Seeds  and  Bulbs  Suitable  for  Tanning. 

Those  of  the  grape  contain  much  tannin,  and  give 
very  good  results.  Those  of  the  wild  cornel  ( hydro - 
sapathum ).  The  bulb  of  the  scilla  maritima,  a  perennial 
plant  indigenous  to  Barbary,  Sicily,  and  Spain.  There 
are  two  varieties  of  squills,  the  red  and  white  bulb,  but 
they  do  not  differ  in  property.  Before  being  sent  to 
market  they  are  thinly  sliced  and  dried. 

According  to  Vogel’s  analysis  100  parts  of  dry  squill 
contain — 


Gum  ........  6 

Bitter  principle  .  .  .  .  .  .  35 

Tannin  ........  24 

Saccharine  matter  ......  6 

Woody  fibre  .......  29 


100 


CHAPTER  X. 

WOODS— ROOTS— BARKS. 

Woods. 

This  material  has  not  been  converted  to  any  useful 
end  so  far  as  it  immediately  concerns  tanning,  notwith¬ 
standing  that  tannin,  as  before  stated,  exists  to  some 
extent  in  many  species. 


78 


CHEMISTRY  OF  TANNING. 


Roots. 

The  dentelaria ,  or  lead  wort  ( Plumbago  Europcea),  a 
perennial  herbaceous  plant  growing  wild  in  the  South 
of  France,  contains  a  considerable  quantity  of  tannin. 
The  malefern  (aspidium  filix  mas ),  grows  in  all  parts 
of  Europe,  and  in  shady  pine  forests  from  New  York  to 
Virginia.  The  best  root  is  about  6  inches  long  and  an 
inch  broad ;  externally  it  is  of  a  brown  color,  internally 
yellowish  or  reddish  white,  with  a  peculiar  but  not  very 
strong  odor,  and  a  sweetish  bitter  nauseous  and  astrin¬ 
gent  taste.  It  is  collected  in  May  and  September. 

Morin  has  analyzed  the  root  and  Peschier  the  buds. 
Morin  found — 

Volatile  oil, 

Fatty  matter  comp,  of  elaine 
and  stearin, 

Gallic  acid, 

Acetic  acid, 

Peschier  found — 

Aromatic  vol.  oil, 

Aromatic  fatty  oil, 

Adipocerous  principle, 

Brown  resin, 

Green  coloring  matter, 

Rhatany  ( krcimeria  triandria)  is  a  native  of  Peru, 
growing  in  dry,  argillaceous,  sandy  places.  It  was  dis¬ 
covered  in  1780  by  Ruitz.  It  consists  of  short  root-stock 
from  half  to  two  inches  in  diameter.  Its  bark  is  dark 
brownish  red,  wrinkled  and  warty  on  the  root-stock, 
brittle,  inodorous,  and  of  a  strongly  astringent  and 
slightly  bitterish  taste.  The  woody  interior  is  yellow¬ 
ish  red,  dense,  tough,  and  of  the  same  taste,  but  much 
weaker. 

According  to  a  recent  analysis  I  made  of  this  root, 
I  found  it  thus  formed : — * 

*  Journal  of  Materia  Medica,  vol.  i.,  new  series,  page  141.  Ana¬ 
lysis  of  Rhatany,  by  Prof.  H.  Dussauce. 


Tannin, 

Uncrystallizable  sugar, 
Starch, 

Ligneous, 

Gelatiniform  matter. 


Reddish  brown  col.  matter, 
Extractive, 

Acetic  acid, 

Chloride  of  potassium. 


WOODS — ROOTS — BARKS. 


79 


Organic  matters  .  .  .  .  .  .  .93.60 

Inorganic  “  .  .  .  .  .  .6.40 


100.00 

Gnm  and  albumen  ......  1- 257 

Sugar  ........  0.285 

Extractive . 0.628 

Starch  ........  1.064 

Tannin  ........  3.928 

Coloring  matter  (resin)  .....  20.578 

Soluble  salts  .......  0.878 

Insoluble  “  .......  5.428 

Ligneous  matter  .......  65.954 


100.000 

Gmelin  found  38.3  of  tannin,  and  Peschier  42.6; 
but  in  those  analyses  they  calculate  the  coloring  matter  as 
tannin. 

Marsh  Rosemary  ( Statica  Caroliniance )  is  found  along 
the  sea-coast  in  marshy  situations  from  Maine  to 
Florida,  flowering  from  August  to  October.  The  root 
is  large,  fusiform  or  branched,  heavy,  fleshy,  and  of  a 
reddish  or  purplish  brown  color.  It  is  inodorous,  but  has 
a  saltish  extremely  bitter  and  astringent  taste.  Accord¬ 
ing  to  Prof.  Parrish  it  contains  12  per  cent,  of  tannin, 
some  gum,  extractive,  albumen,  resin,  volatile  oil,  caout¬ 
chouc,  lignin,  coloring  matter,  and  various  salts. 

Barks. 

The  bark  is  the  outermost  part  of  vegetables.  It 
coveTs  the  whole  plant  from  the  extremity  of  the  roots 
to  the  extremity  of  the  branches.  It  is  usually  of  a 
green  color;  if  a  branch  of  a  tree  be  cut  across,  the  bark 
is  easily  distinguished  from  the  rest  of  the  branch  by 
its  color.  If  we  inspect  such  a  horizontal  section  with 
attention,  we  shall  perceive  that  the  bark  itself  is  com¬ 
posed  of  three  distinct  bodies,  which,  with  a  little  care, 
may  be  separated  from  each  other.  The  outermost  of 
these  bodies  is  called  the  epidermis ,  the  middle  one  is 
called  the  parenchyma ,  and  the  inner  one,  or  that  next 
the  wood,  is  called  the  cortical  layers. 

The  epidermis  is  a  thin,  transparent  membrane,  which 


80 


CHEMISTRY  OF  TANNING. 


covers  all  the  outside  of  the  bark.  It  is  pretty  tough. 
When  inspected  with  a  microscope,  it  appears  to  be 
composed  of  a  number  of  slender  fibres  crossing  each 
other  and  forming  a  kind  of  network.  It  seems  even 
to  consist  of  different  thin,  retiform  membranes,  adhering 
closely  together.  This  at  least  is  the  case  with  the 
epidermis  of  the  birch,  which  M.  Duhamel  separated 
into  six  layers.  The  epidermis,  when  rubbed  off,  is 
reproduced.  In  old  trees,  it  cracks  and  decays,  and  new 
epidermides  are  successively  formed.  This  is  the  reason 
that  the  trunks  of  many  old  trees  have  a  rough  surface. 

Davy  was  induced  by  some  observations  of  Mr.  Coats, 
of  Clifton,  to  examine  the  epidermis  of  the  bamboo,  the 
sugar-cane,  and  the  equisetum  hyemale.  He  found  in 
them  a  great  quantity  of  silica.  When  examined  under 
the  microscope,  the  epidermis  of  these  gramineous  plants 
constitutes  a  brilliant  retiform  tissue,  which  gives  it  the 
harsh  feel  by  which  it  is  distinguished.  The  epidermis 
of  the  bamboo  was  found  to  contain  17.4  per  cent,  of 
silica,  and  it  has  the  appearance,  when  pulverized,  of 
pounded  glass.  He  found  also  silica  in  the  epidermis  of 
the  sugar-cane,  the  common  bog  reed  {arundo phragmites), 
wheat,  barley,  and  oats.  He  found-a  still  greater  propor¬ 
tion  of  silica  in  some  other  of  the  gramineous  plants. 

The  parenchyma  lies  immediately  below  the  epidermis ; 
it  is  of  a  deep  green  color,  very  tender  and  succulent. 
When  viewed  with  a  microscope,  it  seems  to  be  com¬ 
posed  of  fibres  which  cross  each  other  in  every  direction, 
like  the  fibres  which  compose  a  hat.  Both  in  it  and  the 
epidermis  there  are  numberless  interstices,  which  have 
been  compared  to  so  many  small  bladders. 

The  cortical  layers  form  the  innermost  part  of  the 
bark,  or  that  which  is  next  to  the  wood.  They  consist 
of  several  thin  membranes,  lying  one  above  the  other ; 
and  their  number  appears  to  increase  with  the  age  of 
the  plant.  Each  of  these  layers  is  composed  of  longi¬ 
tudinal  fibres  which  separate  and  approach  each  other 
alternately,  so  as  to  form  a  kind  of  network.  The 
meshes  of  this  network  correspond  in  each  of  the  layers, 
and  they  become  smaller  in  every  layer  as  it  approaches 


WOODS — ROOTS — BARKS. 


81 


the  wood.  These  meshes  are  filled  with  a  green-colored 
cellular  substance,  which  has  been  compared  by  anato¬ 
mists  to  a  number  of  bladders  adhering  together,  and 
communicating  with  each  other. 

Fourcroy  supposes  that  the  epidermis  is  the  same  in 
its  nature  in  all  trees,  and  that  it  possesses  constantly 
the  properties  of  cork ;  but  this  opinion  is  likely  not  to 
be  verified.  The  cortical  layers  seem,  at  least,  in  many 
cases,  to  have  a  similar  fibrous  basis ;  a  basis  possessing 
essentially  the  properties  of  flax,  which  is  itself  merely 
the  cortical  layers  of  linum  usitatissimum.  Common 
cork,  which  constitutes  the  epidermis  of  the  quercus 
suber,  is  composed  of  a  cellular  tissue,  whose  cavities 
contain  a  variety  of  foreign  substances,  which  may  be 
separated  by  rasping  down  the  cork  and  treating  it  by 
various  reagents,  as  is  done  with  wood,  in  order  to  free 
the  lignin  from  foreign  matters.  Ten  parts  of  common 
cork,  when  treated  in  this  way,  are  reduced  to  seven. 
This  residue  was  considered  by  Chevreul  as  a  peculiar 
substance,  which  he  distinguishes  by  the  name  of 
suberin. 

The  properties  of  suberin  have  not  been  yet  accu¬ 
rately  determined,  owing  to  the  difficulty  of  obtaining 
it  in  a  state  of  purity.  Sulphuric  acid  readily  chars  it. 
Nitric  acid  gives  it  a  yellow  color,  corrodes,  dissolves, 
and  decomposes  it;  converting  it  partly  into  suberic 
acid,  partly  into  a  substance  resembling  wax,  partly 
into  artificial  tannin,  and  partly  into  a  kind  of  starchy 
matter. 

Suberin  is  very  inflammable,  burning  with  a  lively 
flame,  while  at  the  same  time  it  swells  considerably,  but 
does  not  melt.  When  distilled  it  yields  water  and  a 
colorless  oil,  then  a  yellow  colored  oil.  These  liquids 
are  all  acids.  If  the  distillation  be  continued,  a  brown 
oil  comes  over  with  a  little  ammonia,  and  a  fatty  crys- 
tallizable  substance,  which  does  not  dissolve  in  caustic 
potash.  During  the  process,  combustible  gases  are  dis¬ 
engaged,  and  there  remains  a  porous  charcoal,  weighing 
one-fourth  part  of  the  suberin  employed. 

Chevreul  heated  given  weights  of  common  cork, 
6 


82 


CHEMISTRY  OF  TANNING. 


washed  cork,  and  suberin  with  nitric  acid,  and  obtained 
the  following  products : — 


Common 

Washed 

Cork. 

Cork. 

StJBEEIN. 

Fibrous,  white,  insoluble  matter 

0.18 

0.9 

1.0 

Resia  ..... 

1 4  72 

17.5 

10.0 

Oxalic  acid  .... 

16.00 

10  6 

7.6 

Suberic  “  .... 

14.40 

19.6 

22.4 

45.30 

46.6 

41.0 

What  is  wanting  to  constitute  the  100  parts  is  a  yel¬ 
low  bitter  substance  held  in  solution  by  the  mother 
water,  together  with  carbonic  acid  and  water  formed  at 
the  expense  of  the  constituents  of  cork. 

Chevreul  obtained  from  the  epidermis  of  the  birch, 
cherry  tree,  and  plum  a  quantity  of  suberic  acid,  which 
was  always  the  greater  the  purer  the  epidermis  em¬ 
ployed.  Hence  it  would  appear  that  these  epidermides 
have  a  constitution  analogous  to  that  of  cork.  According 
to  John,  the  young  epidermis  of  the  birch  differs  essen¬ 
tially  from  cork  in  this  respect.  It  is  soluble  by  boiling 
in  caustic  potash  lye,  and  when  the  brown-colored  solu¬ 
tion  is  treated  with  an  acid,  yellow  flocks  fall,  which 
become  brown  on  drying.  This  precipitate  is  slightly 
soluble  in  boiling  alcohol,  but  most  of  it  falls  again 
when  the  solution  cools.  The  matter  of  the  paren¬ 
chyma,  and  the  juice  which  exists  in  bark,  vary  ex¬ 
tremely,  and  probably  occasion  most  of  the  differences 
between  them.  Some,  as  oak  barks,  are  characterized 
by  their  astringency,  and  contain  tannin ;  others,  as 
cinnamon,  are  aromatic,  and  contain  an  essential  oil  ; 
others  are  bitter,  some  are  chiefly  mucilaginous,  others 
resinous,  etc.  But  in  the  present  state  of  the  subject, 
an  enumeration  of  the  different  kinds  of  bark  is  not  to 
be  expected ;  I  shall,  therefore,  satisfy  myself  with 
detailing  the  properties  of  those  barks  that  have  been 
subjected  to  examination  in  the  art  of  tanning. 

Cinnamon. — Laurus  cinnamomum  is  a  tree  growing 
from  20  to  30  feet  high,  with  a  trunk  from  a  foot  to  a 
foot  and  a  half  in  diameter  and  covered  with  a  thick 
scabrous  bark.  This  tree  is  a  native  of  Ceylon,  the 
Malabar  coast,  Sumatra,  Borneo.  The  bark  of  the  root 


WOODS — ROOTS — BARKS. 


83 


has  the  odor  of  cinnamon  with  the  pungency  of  cam¬ 
phor.  The  leaves  have  a  hot  taste.  The  flowers  have 
a  disagreeable  odor,  similar  to  that  exhaled  from  freshly- 
sawn  bones.  The  bark  furnishes  the  cinnamon  of  com¬ 
merce.  It  is  usually,  collected  from  trees  about  nine 
years  old.  The  peeling  commences  in  May  and  lasts 
until  the  latter  part  of  September.  The  bark  is  dried 
in  the  shade  first,  and  finished  in  the  sun.  The  best 
bark  comes  from  Ceylon.  It  has  a  light  yellowish-brown 
color.  It  possesses  a  rich,  pure,  peculiar  odor,  and  a 
sweetish,  aromatic,  slightly  astringent,  pungent,  and 
peculiar  taste.  It  yields  its  virtues  to  water  and  alcohol. 
Its  tannin  is  of  the  same  nature  as  the  catechu  tannin ; 
it  gives  a  dark  green  precipitate  with  the  salts  of  iron. 
There  are  several  other  species  of  cinnamon,  as  the 
C.  aromaticum ,  C.  nitidum ,  C.  tamala ,  C.  Loureirii ,  C. 
culilawan. 

Vauquelin  has  analyzed  two  kinds,  and  found  them 
thus  formed : — 


Cinnamon  of  Cayenne. 
Volatile  oil  with  a  smart  taste. 
Tannin. 

Gum. 

Salts  of  potash  and  lime. 


Cinnamon  of  Ceylon. 
Volatile  oil  more  agreeable. 
Tannin. 

Coloring  matter. 

Gum. 

Resin. 


Sassafras. — Laurus  sassafras  is  a  well-known  tree 
growing  through  the  United  States  and  extending  into 
Mexico,  and  flowering  in  the  latter  part  of  April  or 
early  in  May.  The  flowers  have  a  weak  agreeable 
odor.  The  bark  of  the  root  is  in  small  irregular  pieces 
of  a  grayish-brown  color  outside,  rusty-brown  within. 
Hot  water  and  alcohol  take  up  its  active  properties. 

According  to  Reinsch,  it  is  thus  formed : — 


Water 

•  • 

9.0 

Essential  oil 

.  . 

0.8 

Fatty  matter 

• 

0.8 

Balsamic  resin  and  wax 

5.0 

Sassafride  ) 

extracted  by 

9.2 

Tannin  \ 

strong  acohol 

5.8 

Soluble  albumen  . 

0.6 

Sassafride  ) 

Tannin  >  ext.  by  w'k  alcohol  6.8 
Gum  ) 

Gum ,  col.  matter  and  salts  3.0 
Fecula,  tannin  (by  water)  5.4 
Fecula ,  tannin  {by  caustic  lye )  28.9 
Lignin  24.7 


100.0 


84 


CHEMISTRY  OF  TANNING. 


Birch  Bark. — Betula  alnus ,  tree  which  abounds  in  the 
dry,  barren  portion  of  the  Middle  States,  and  grows  to  a 
great  height.  The  epidermis  consists  of  thin  white 
layers.  The  inner  bark  is  astringent,  and  is  used  for 
tanning  Russia  leather.  According  to  Davy  it  contains 
6.75  per  cent,  of  tannin.  Russia  leather  owes  its  odor 
and  durability  to  a  fragrant  brown  oil  it  contains. 

Chestnut  Bark.  Castanea  vesca. — We  have  already 
mentioned  the  chestnut-tree.  The  American  species 
grows  in  gravelly  or  sandy  soils,  and  yields  a  bark  which 
contains  upwards  of  four  per  cent,  of  tannin.  Leather 
tanned  with  it  possesses  greater  solidity  and  flexibility 
than  that  made  with  oak  bark. 

Horse-Chestnut. — JBsculus  hippocastanuvi  is  indige¬ 
nous  to  this  country,  but  is  cultivated  in  Europe.  Ac¬ 
cording  to  Davy  it  contains  1.875  per  cent,  of  tannin. 
The  American  variety  is  known  as  Ohio  Buckeye. 

Beech  Bark.  Fagus  sylvatica. — Indigenous  to  the 
North  of  Europe  and  North  of  America.  Is  very  abun¬ 
dant  in  New  York,  Pennsylvania,  Kentucky,  and  Ten¬ 
nessee.  It  is  classified  into  two  varieties,  the  white,  fagus 
sylvestris — and  the  red,  fagus  ferruginea.  Beech  bark 
is  of  a  silvery  color,  and  contains  nearly  three  per  cent, 
of  tannin.  In  places  where  oak  is  scarce  the  white 
beech  is  used  for  tanning  purposes,  and  makes  a  white 
but  inferior  leather. 

Lombardy  Poplar  Bark. — Populus fastigiata  contains 
3.12  of  tannin,  and  makes  a  lighter-colored  leather  than 
oak  bark,  imparting  at  the  same  time  a  fragrant  odor 
similar  to  that  of  Russia  leather. 

Black  Thorn  Bark. — Prunus  spinosa,  from  the  sloe 
tree  or  wild  plum  tree,  contains  3.32  of  tannin.  The 
black  thorn  of  the  United  States  is  the  yellow  cratcegus. 

Pomegranate  Bark. — Punica  granatum  is  a  shrubby 
tree  of  African  origin.  It  is  cultivated  in  the  southern 
States.  There  are  two  varieties,  distinguished  by  their 
fruit;  one  is  sour  and  the  other  sweet.  The  rind  of  the 
fruit,  the  flowers,  bark  of  the  root  abound  in  tannin. 

Ash  Bark. — Fraxinus  excelsior  is  abundant  in  our 
forests  and  grows  to  a  great  height.  The  leaves  and 


WOODS — ROOTS — BARKS. 


85 


bark  have  a  very  astringent  taste.  According  to  Davy 
the  bark  contains  8.33  per  cent,  of  tannin. 

Elm  Bark.- — TJlmus  campestris  is  cultivated  in  the 
United  States,  and  contains  2.706  of  tannin. 

Cinchona  Bark  grows  in  South  America,  and  the 
number  of  species,  as  described  by  Guibourt,  amounts 
to  25,  but  as  many  more  have  been  described  since. 

As  this  bark  is  very  costly  and  used  only  in  medicine, 
we  do  not  think  it  necessary  to  describe  it  here.  All 
the  cinchona  barks  are  very  rich  in  tannin. 

Poison  Oak. — Rhus  toxicodendron  is  a  creeping  shrub 
from  one  to  three  feet  high.  The  leaves  are  inodorous, 
have  a  mawkish  acrid  taste,  and  yield  their  virtues  to 
alcohol  and  water.  It  grows  wild  through  the  United 
States.  This  plant  contains  tannin  and  gallic  acid. 

Sumach.  Rhus  glabrum. — In  its  purity  it  consists  of 
the  powdered  leaves  of  a  shrub  that  grows  extensively 
in  the  South  of  European  the  United  States  and  in  Asia, 
to  which  it  is  indigenous.  It  seems  that  there  are  several 
species,  such  as  the  Wild  Olive,  Rhus  cotinus,  rhus  gla¬ 
brum  or  coriaria,  which  is  the  best  and  most  esteemed 
for  the  preparation  of  the  finer  kinds  of  leather.  Italy, 
Sicily,  Portugal,  Spain,  and  France  produce  considerable 
quantities  of  sumach,  varying  in  quality,  and  distin¬ 
guished  from  one  another  by  the  habits  of  the  tree,  the 
color  and  other  properties.  The  sumach  obtained  from 
the  rhus  cotinus  is  for  the  most  part  employed  in  dyeing, 
and  the  product  of  the  rhus  coriaria  is  that  which  is 
converted  to  the  uses  of  the  tanner,  especially  in  the 
preparation  of  morocco  and  similar  leather.  The  latter 
shrub,  which  grows  wild  in  Portugal,  Spain,  and  other 
countries  named  above,  rises  to  the  height  of  four  to 
eight  and  in  some  cases  to  12  feet;  its  stem  is  crooked 
and  covered  with  a  reddish-gray  bark;  the  leaves  present 
•  a  green  on  the  upper,  and  a  whitish  color  on  the  under 
surface  during  spring  and  summer,  but  they  assume  a 
reddish  hue  in  autumn.  It  flowers  in  July,  the  blossom 
being  greenish-red,  and  yields  a  cluster  of  small  crimson 
berries  on  ripening.  Regarding  the  effects  of  sumach 
as  a  tanning  agent,  it  is  stated  that  it  deprives  the  skin 


86 


CHEMISTRY  OF  TANNING. 


of  much  of  its  softness  and  elasticity,  but  it  offers  a  great 
advantage  of  not  coloring  it  during  the  process,  and  is 
on  this  account  preferred  in  France  and  other  places, 
notwithstanding  its  cost  being  much  greater  than  other 
tanning  agents,  by  the  fabricators  of  morocco  and  glazed 
leather.  It  is  utilized  in  the  ordinary  way  of  tanning 
mixed  with  bark  or  other  matters,  and  affords  good 
results. 

Of  the  species  of  sumach  in  the  market,  the  Sicilian 
is  accounted  the  best.  There  are  two  kinds,  one  of 
which,  the  alcamo,  is  the  most  esteemed.  It  is  a  very 
fine  light  green  powder,  containing  very  little  woody 
matter,  having  an  agreeable  odor  analogous  to  that  of 
the  violet  and  a  strong  astringent  taste.  It  contains 
very  little  coloring  matter,  though  it  gives  a  yellowish- 
green  solution  when  macerated  with  water.  The  second 
variety  inclines  to  a  reddish-yellow,  has  a  feebler  odor, 
with  a  less  astringent  taste  than  the  foregoing  variety. 
Sicilian  sumach  is  generally  packed  in  bales  weighing 
about  one  hundred  and  a  half. 

Spanish  sumach  is  various  in  quality,  being  less  care¬ 
fully  prepared,  and,  consequently,  more  or  less  mixed 
with  woody  matters.  The  best  sort  comes  from  Priego, 
and  is  grown  in  the  neighborhood  of  Malaga.  It  is, 
like  the  Sicilian,  finely  ground,  and  affords  a  color  of 
equal  or  greater  brightness ;  its  odor  reminds  one  of  the 
tea  plant.  With  water  it  gives  a  dark  and  more  red¬ 
dish  solution  than  the  foregoing.  It  is  usually  packed 
in  bales  of  one  hundred  weight;  the  other  sort,  the 
Molina  and  Valladolic  sumach,  are  next  in  quality  to 
the  foregoing ;  they  are  very  similar. 

Portuguese  or  Porto  sumach  is  almost  similar  to  the 
Priego,  but  is  generally  dirtier,  and  contains  more 
mineral  salts. 

Italian  sumach  has  a  dark  green  color,  is  free  from 
woody  matter,  but  feels  granular  in  the  hand,  and  has 
an  odor  like  that  of  the  bark,  which  possesses  similar 
qualities  to  the  leaves. 

French  sumach  is  similar  to  the  preceding.  Three 
sorts  are  collected:  the  fauvis  is  almost  equal  to  the 


WOODS — ROOTS — BARKS. 


87 


Sicilian  when  well  purified,  and  comes  from  Brignolles, 
near  Marseilles.  If  less  care  be  taken  in  its  manufac¬ 
ture,  it  approaches  more  to  the  quality  of  Malacca  su¬ 
mach — it  frequently  goes  under  both  these  names.  A 
second  sort,  Donzere,  and  a  third,  Pudis,  are  commonly 
used  in  the  tanneries.  A  fourth  variety,  called  redou  or 
redoul ,  obtained  from  the  coriaria  myrtifolia ,  cultivated 
in  Languedoc,  is  of  a  grayish  green  color. 

Willow  Bark.  Salix  alba. — This  bark  is  remarkable 
for  its  astringent  taste.  This  tree  grows  in  the  north¬ 
ern  and  temperate  parts  of  North  America.  The  dry 
bark  has  an  ash-gray  color  on  the  upper  and  a  reddish 
yellow  on  the  under  surface.  The  white  willow  con¬ 
tains  2.3  per  cent,  of  tannin  and  the  Leicester  willow 
6.86  per  cent.  The  black  willow  is  the  most  common 
American  willow,  and  grows  in  the  Western  and  Middle 
States.  In  the  North  of  Europe  the  S.  alba  is  used  for 
tanning. 

The  leather  which  is  made  from  kid  and  lamb-skins 
owes  its  agreeable  odor  to  the  willow  bark  with  which 
it  is  tanned. 

Tamarisk — Tamarix  gallica — is  a  shrub  plant  indi¬ 
genous  to  Spain,  Italy,  and  the  South  of  France.  The 
bark  is  deep  reddish  brown  on  the  upper  and  yellowish 
on  the  under  side  ;  both  the  wood  and  bark  have  an 
astringent  slightly  bitter  taste. 

Hemlock  Bark.  Abies  canadensis. — This  tree  some¬ 
times  attains  the  height  of  30  feet,  with  a  trunk  two  or 
three  feet  in  diameter.  Its  foliage  is  delicate  bright 
green  above  and  silvery  white  underneath.  Hemlock 
is  abundant  in  Canada,  Nova  Scotia,  and  the  elevated 
and  mountainous  regions  of  New  England  and  the  Mid¬ 
dle  States.  Its  timber  is  very  coarse  grained,  and  its 
bark  contains  an  astringent  principle.  The  bark  is 
largely  used  in  this  country  as  a  substitute  for  that  of 
the  oaks  in  tanning.  It  imparts  its  red  color  to  leather 
made  with  it,  which  is  said  to  be  inferior  to  that  made 
with  oak  bark ;  but  the  two  kinds  united  are  supposed 
to  produce  better  leather  than  either  of  them  alone. 


88 


CHEMISTRY  OF  TANNING. 


CHAPTER  XI. 

OAK  BARKS. 

The  oak,  by  its  strength  and  greatness,  is  the  patri¬ 
arch  of  the  forest.  It  lives  three  or  four  hundred  years, 
and  some  authors  have  ascertained  that  it  has  lived  six 
hundred  years,  according  to  the  fertility  and  exposure 
of  the  ground.  It  is,  and  will  always  be,  the  most  use¬ 
ful  of  trees.  It  seems  that  such  a  tree  ought  to  be  well 
known  in  its  botanical,  physical,  and  industrial  cha¬ 
racter  ;  but  such  is  not  the  case,  and  unhappily  all  the 
varieties  of  oak  are  not  yet  known.  The  different  species 
of  oak  belong  to  the  monoecia  polyandria ;  all  the  parts 
and  principally  the  bark  contain  tannin.  We  shall 
divide  them  into  two  classes : — 

l.  European  oaks.  2.  American  oaks. 

1.  European  Oaks. 

Quercus  robur. — This  bark,  so  long  and  universally 
employed  for  tanning  leather,  has  been  but  imperfectly 
examined.  Davy  found  that  100  parts  contain  12.7 
parts  of  extractive  and  6.3  of  tannin.  It  contains  also 
a  considerable  quantity  of  pectin.  When  oak  bark, 
after  having  been  exhausted  by  tannin,  is  put  into  water, 
a  kind  of  fermentation  takes  place,  and  an  acid  liquid  is 
formed,  which  is  employed  in  one  of  the  preliminary 
processes  of  tanning.  The  acid  thus  formed  is  the  lactic, 
and  the  liquid,  called  jusee  by  the  Trench,  contains  ace¬ 
tate  of  lime,  tannin,  apotheme,  a  gummy  matter,  free 
acetic  acid,  and  a  great  quantity  of  lactate  of  lime  to¬ 
gether  with  lactate  of  magnesia,  potash,  ammonia,  and 
probably  of  manganese  and  iron. 

Quercus  nigra. 

Quercus  glomerata. 

Quercus  lamiginosa. 

Quercus  laciniata. 

Quercus  viminalis. 

Quercus  pedunculata  contains  about  as  much  tannin 
as  the  quercus  robur. 


OAK  BARKS. 


89 


Quercus  cerris. 

Quercus  haliphceos. 

Quercus  tauza. 

Quercus  esculus  grows  in  Italy  and  Dalmatia. 

Quercus  apennina  grows  in  Italy  and  the  East. 

Quercus  lastigiata  grows  South  of  France. 

Quercus  lusitanica. 

Quercus  infectoria. 

Quercus  Ilex  grows  in  Spain,  Italy,  and  the  South  of 
France.  Is  much  used  to  tan  leather. 

Quercus  suber  grows  in  the  South  of  Europe,  princi¬ 
pally  in  Spain.  It  requires  dry  and  warm  lands  and 
fears  the  damp  cool.  Its  height  is  from  24  to  30  feet. 
Its  bark  is  very  thick  and  soft  and  is  known  by  the  name 
of  cork.  It  falls  naturally  every  seven  or  eight  years. 
It  is  used  for  tanning  and  burning,  and  after  the  tree 
has  attained  the  age  of  thirty,  the  bark  is  collected 
regularly  every  seven  or  eight  years  to  manufacture  the 
cork.  M.  Chevreul  has  analyzed  it  and  found  it  thus 
formed : — 

Wax.  Gallic  acid. 

Cerine.  Suberin. 

Soft  resin.  Acetic  acid. 

Red  coloring  matter.  Brown  nitrogenized  matter. 

Tannin.  A  salt  of  lime. 

Quercus  coccifera  is  known  by  the  name  of  dwarf 
oak  and  garouille.  Its  height  is  from  3  to  4  feet.  The 
bark  of  the  root  is  very  rich  in  tannin  and  much  used 
in  Europe  for  tanning.  It  is  on  this  oak  that  grows 
the  vegetable  kermes  called  vermilion ,  Coccus  Ilicis.  Ac¬ 
cording  to  M.  Bose,  the  leaves  and  trunks  can  be  used 
in  tanning.  It  is  much  used  in  the  South  of  France. 

When  this  bark  is  used,  the  ox-hides  are  placed 
about  40  in  a  vat  with  plenty  of  water.  In  the  vat  is 
first  put  a  small  quantity  of  bark.  Increase  progres¬ 
sively  the  quantity  of  bark  until  about  one*  third  of  the 
bark  destined  to  tan  the  hides  is  used.  During  the 
time,  which  lasts  three  months  for  heavy  leather,  draw 
and  drop  the  hides,  and  put  them  back  in  the  liquid. 


90 


CHEMISTRY  OF  TANNING. 


Leave  them  again  three  weeks,  when  draw  them  to  put 
them  into  the  pits. 

The  barking  of  this  tree  is  done  in  every  season ; 
however,  it  is  richer  in  tannin  in  the  spring.  In  June 
it  contains  8.9  per  cent,  of  tannin,  and  in  September 
only  8.3  per  cent. 

2.  American  Oaks. 

White  Oak.  Quercus  alba. — This  tree  varies  in  size 
according  to  the  climate  and  soil,  attaining  the  height 
of  from  60  to  90  feet  with  a  diameter  of  from  3  to  6 
feet.  It  grows  throughout  the  Union,  but  is  more 
abundant  in  the  Middle  States.  Its  wood  is  strong  and 
durable,  and  is  extensively  employed  in  ship  building, 
etc.  The  bark  is  employed  for  tanning,  but  the  red  and 
Spanish  oaks  are  preferred.  The  bark  contains  much 
tannin ;  it  has  a  light  yellowish  brown  color,  a  feeble 
odor,  and  a  strongly  astringent  bitterish  taste. 

The  black  oak  is  a  forest  tree  common  to  the  United 
States,  the  bark  of  which  is  much  used  in  tanning.  It 
is  preferable  to  the  above.  Its  coloring  principle  is 
known  by  the  name  of  quercitrin. 

The  red,  oak  is  more  common  in  the  Northern  States 
and  Canada;  its  wood  is  reddish  and  coarse-grained, 
and  used  principally  for  fuel.  It  contains  considerable 
tannin. 

Quercus  Phoellos  grows  in  North  America ;  its  height 
is  about  100  feet. 

Quercus  primus  is  found  in  North  and  South  Carolina. 
Its  height  is  about  99  feet. 

Quercus  aquatica  grows  in  North  and  South  Carolina. 

Quercus  coccinea,  or  scarlet  oak ,  is  more  abundant  in 
the  Middle  States,  and  on  the  mountains  of  Carolina 
and  Georgia,  but  is  found  as  far  north  as  latitude  43°. 
Its  height  is  about  80  feet  and  its  diameter  3  or  4.  Its 
leaves  are  of  a  beautiful  green,  and  the  first  frost  turns 
them  a  bright  scarlet  color.  This  tree  produces  galls, 
which  are  applied  to  the  same  purposes  as  the  European 
galls. 

Quercus  virens ,  or  lice  oak ,  is  confined  to  the  vicinity 


OAK  BARKS. 


91 


of  the  x\tlantic  coast,  south  of  latitude  37°  aud  of  the 
Gulf  of  Mexico  as  far  as  the  river  Sabine.  Its  height  is 
from  40  to  50  feet,  and  its  diameter  from  1  to  2  feet-. 
The  leaves  have  a  dark  green  color  above,  and  whitish 
beneath. 

The  bark  is  hard  and  thick,  and  of  a  blackish  color. 
It  is  very  good  for  tanning  leather,  but  is  not  much 
employed. 

Quercus  falcata,  or  Spanish  oak,  inhabits  all  those 
parts  of  the  Union  which  are  south  of  the  41st  parallel 
of  latitude,  but  is  most  abundant  in  the  Atlantic  States. 

This  oak  is  remarkable  for  the  great  dissimilitude 
which  exists  in  its  leaves  and  general  appearance  in 
different  climates.  In  the  Southern  States  it  grows  to 
the  height  of  30  feet  with  a  trunk  4  or  5  feet  in  dia¬ 
meter,  while  in  New  Jersey  it  is  never  above  30  feet 
high,  with 'a  trunk  4  or  5  inches  thick.  The  bark  is 
thick,  black,  and  deeply  furrowed,  and  the  wood  is  red¬ 
dish  and  cross-grained,  with  open  pores.  The  leaves  on 
the  tree  in  the  South  are  falcate,  and  as  well  as  the 
young  shoots  to  which  they  are  attached  are  covered 
with  a  thick  down  upon  the  under  sides.  In  New 
Jersey  the  leaves  are  three  lobed,  except  a  few  upon 
the  summit,  which  are  slightly  falcated.  This  tree 
fructifies  once  in  two  years.  Its  flowers  put  forth  in 
May,  and  are  succeeded  by  small  round  brown  acorns, 
contained  in  scaly,  shallow  cups,  supported  by  peduncles 
one-sixth  of  an  inch  in  length.  The  Spanish  oak  is  chiefly 
valuable  on  account  of  its  bark,  which  is  preferred  to 
any  other  for  tanning  coarse  leather,  which  it  is  supposed 
to  render  whiter  and  more  supple.  The  quality  of  the 
leather  prepared  with  it  is  said  to  be  improved  by  the 
addition  of  a  small  quantity  of  hemlock. 

Quercus  amhigua ,  or  grag  oak ,  is  abundant  in  Maine, 
New  Hampshire,  and  in  Vermont.  Its  height  is  50  to 
60  feet,  and  its  diameter  15  or  18  inches.  The  leaves 
are  large  and  smooth.  It  flowers  in  May.  The  wood 
aud  bark  are  similar  to  those  of  the  red  oak,  and  the  latter 
may  be  employed  in  tanning. 


92 


CHEMISTRY  OF  TANNING. 


CHAPTER  XII. 

BARKING  OF  THE  TREES. 

PART  OP  THE  BARK  CONTAINING  THE  MOST  TANNIN — AGE  OF  THE  TREES 
RELATIVELY  TO  THE  RICHNESS  IN  TANNIN  FROM  THEIR  BARKS — BARK¬ 
ING  OF  THE  TREES — INFLUENCE  OF  THE  SEASON  AND  LOCALITIES,  IN 
THE  TIME  OF  THE  BARKING. 

Parts  of  the  Bark  containing  the  most  Tannin. —  We 
have  already  stated  that  bark  is  composed  of  four  parts  ; 
all  are  not  equally  rich  in  tannin,  or  rather  some  contain 
none.  Such  is  the  case  with  the  epidermis,  the  liber 
contains  very  little.  It  is  in  the  inner  layer  of  the 
cortex  that  it  is  principally  found.  Davy  has  found  in 
oak  bark  of  middling  size  and  cut  in  the  spring  0.604, 
while  the  inside  white  layers  have  given  him  ^).15.  The 
experiments  of  tanners  have  demonstrated  the  fact. 
We  see  then  theory  and  practice  agree  together.  This 
remark  is  of  much  interest  for  the  tanner  who  ought  to 
reject  the  bark,  with  a  thick  epidermis,  as  poor  in  tannin. 
It  is  the  same  case  with  medicinal  astringent  barks. 
Indeed  quinquina  barks  are  as  poor  in  tanning  princi¬ 
ples,  quinia  and  cinchona,  as  they  are  more  fibrous  or 
ligneous,  while  if  the  break  is  less  fibrous,  smoother,  with 
a  resinous  aspect,  they  are  richer  in  those  principles. 

Age  of  the  Trees  Relatively  to  the  Richness  of  their 
Barks  in  Tannin. — It  is  a  great  mistake,  which  unhap¬ 
pily  is  believed  by  a  great  many,  that  the  older  the 
bark  the  poorer  in  tannin ;  however,  while  we  have  no 
doubt  our  opinion  will  be  regarded  as  erroneous,  we  do 
not  hesitate  to  say  that  the  older  the  hark  the  richer  it  is 
in  tannin.  In  this  country  this  fact  has  been  well  un¬ 
derstood,  as  tanners  use  only  barks  of  old  trees.  In 
Europe  they  employ  only  young  trees  from  18  to  30 
years  old.  There  is  great  variance  of  opinion  regarding 
the  age  of  oak  to  give  a  good  bark.  In  some  places 
they  bark  after  10  or  12  years,  in  some  others  they 
require  a  bark  20  years  old.  In  this  country  we  use 
barks,  no  matter  how  great  their  age,  with  the  convic¬ 
tion  that  the  tanning  part  never  loses  its  properties. 


BARKING  OF  THE  TREES. 


93 


If  the  bark  is  covered  with  moss,  it  is  taken  out  with 
the  black  and  rough  parts. 

In  some  countries  they  bark  the  trees  while  standing, 
in  others  they  bark  only  after  being  cut.  This  last 
method  is  the  best,  for  in  barking  the  trees  while  stand¬ 
ing  they  eause  a  considerable  damage  to  the  woods. 
However,  according  to  Buffon,  if  the  tree  must  be  cut  a 
short  time  after,  it  is  no  harm  to  bark  while  standing. 

Barking  and  the  Most  Convenient  Time  for  it. — Ex¬ 
periment  has  demonstrated  that  it  is  in  the  spring, 
when  the  sap  is  in  full  activity,  that  the  bark  should  be 
taken.  We  have  said  that  all  the  regenerating  and 
vivifying  power  resided  in  the  bark.  The  suckers,  the 
slips,  the  buds  present  us  a  proof  of  this  first  fact. 
Willow,  olive  trees,  mulberries,  and  a  multitude  of 
others,  the  trunks  of  which  are  entirely  rotted  and  the 
bark  alone  forms  the  partition.  These  trees,  full  of 
strength,  are  covered  with  leaves  and  flowers.  This  is 
due  to  the  great  quantity  of  nutricious  juices  conveyed 
by  the  bark.  These  abundant  juices  are  sometimes 
different  from  those  of  the  wood.  Often,  also,  while  of 
the  same  nature  they  are  in  so  great  a  proportion  that 
they  break  the  bark  to  exude,  or  it  is  sufficient  to  make 
some  incisions  to  have  them  run  out.  Almond  trees, 
acacias,  apricot  trees,  etc.,  are  an  example.  It  results 
from  these  facts,  that  while  the  sap  is  abundant  in  the 
bark  in  the  spring,  principally  towards  May,  it  is  the 
proper  time  for  barking.  Tannin,  as  we  have  demon¬ 
strated,  exists  in  the  sap  of  several  vegetables,  and  in¬ 
dependently  of  numerous  experiments  of  tanners,  which 
demonstrate  the  superiority  for  tanning  of  the  bark  cut 
in  the  spring,  chemical  analysis  throws  light  on  this 
important  fact.  Indeed,  Davy  has  demonstrated  that 

Oak  bark  cut  in  the  spring  contains  of  tannin  .  6.04 

“  “  “  fall  “  “  “  .  4.385 

Which  gives  nearly  one-third  more  in  the  spring.  Here 
again  theory  agrees  with  practice,  both  command  to 
choose  the  spring  as  the  time  when  the  bark  is  richer 
in  sap  and  tannin.  Then  we  must  cut  every  kind  of 


94 


CHEMISTRY  OF  TANNING. 


oak  at  the  time  when  the  sap  is  up,  and  the  barking 
must  be  done  immediately  by  cutting  circularly  the 
bark  from  the  trunk  at  both  ends,  and  splitting  it  lon¬ 
gitudinally.  The  bark  is  dried  slowly  in  the  shade. 

Influence  of  Seasons  and  Place  at  the  Time  of  Barking 
on  the  Richness  in  Tannin. — We  have  said  above  that 
the  spring  is  the  best  time  to  bark,  but  this  time  may 
be  more  or  less  advanced  according  to  the  temperature. 
Thus,  if  the  winter  has  been  severe  and  the  spring  cold, 
it  will  be  only  in  the  middle  or  the  end  of  May  that 
vegetation  will  begin,  and  the  barks  will  not  be  so  rich 
in  tannin.  On  the  contrary,  if  the  winter  has  been 
mild  and  the  spring  warm,  April  is  the  most  convenient 
time.  In  temperate  climates  it  is  by  the  end  of  April, 
or  the  beginning  of  May,  that  this  operation  takes 
place.  The  barks  are  as  much  richer  in  tannin  as  they 
come  from  trees  of  warm  countries,  i.  e.,  the  tannin  is 
developed  in  greater  proportions  the  further  south  it  is. 
In  the  same  locality  oaks  well  exposed  to  the  south  and 
in  dry  and  elevated  places  give  barks  richer  in  tannin. 
On  the  contrary,  if  they  are  in  the  shade  in  a  low  and 
damp  locality  they  contain  less.  It  is  the  same  for 
rainy  seasons,  which  have  great  influence  in  the  pro¬ 
duction  of  tannin.  The  barks  are  aqueous  and  sur- 
saturated  with  vegetable  matter.  These  facts,  while 
apparently  trifling,  are  of  great  interest  to  tanners. 

Decrease  in  Weight  of  Smooth  Bark  when  Exposed  to 
the  Air. — Every  tanner  knows  that  his  bark  is  some¬ 
what  heavier  when  it  first  comes  from  the  store,  than 
after  it  has  been  exposed  for  some  time  to  the  sun  and 
air,  and  that  it  is  therefore  more  advantageous  to  sell  it 
before  it  leaves  the  store,  instead  of  after  it  has  lost 
some  of  its  weight  under  the  above  circumstances.  It 
will  also  be  to  his  interest  to  learn  how  great  a  loss  in 
weight  the  stored  bark  is  liable  to,  when  placed  in  the 
open  air. 

In  order  to  ascertain  this,  Professor  Nordlinger* 
allowed  a  bundle  of  smooth  bark  weighing  about  29 


*  Gerber  Zeitung.  Berlin,  Prussia. 


BARKING  OF  THE  TREES. 


95 


lbs.,  brought  from  the  Hohenheim  bark  forests,  which 
had  reached  its  15th  year  of  growth,  and  whose  strongest 
limbs  were  slightly  split  at  the  foot,  to  remain  laid  flat 
in  a  plastered  room,  having  little  draught  through  it, 
during  May  and  June.  On  the  26th  of  June  he  took 
the  bark  out  at  about  eleven  o’clock  in  the  morning, 
and  exposed  it,  loosely  spread  out  on  trestles,  to  a  toler¬ 
ably  strong  wind,  and  a  bright  but  not  very  warm  sun 
heat — temperature  75°  in  the  sun,  and  72|°  in  the 
shade — and  found,  after  weighing  it  again,  that  he  had 
sustained  a  loss  in  weight,  that  is  to  say,  a  loss  in  mois¬ 
ture  of  0.187,  upon  the  store  weight,  and  0.191  after 
being  dried  by  the  wind,  being  about  2  per  cent,  of  the 
weight  of  the  bark. 

In  order  to  determine  the  degree  of  loss  that  a  more 
thorough  drying  would  cause,  the  small  bundle  of  bark 
was  again  taken  out  of  the  store-room  on  a  warm  cloud¬ 
less  day,  the  14th  of  July,  and  laid  upon  the  groud  in 
the  open  air  as  before,  where  it  was  allowed  to  remain 
from  9  o’clock  in  the  morning  until  half-past  two  in  the 
afternoon.  The  sun  was  quite  strong,  93°  in  the  shade, 
and  97|  in  the  sun,  with  little  motion  in  the  air.  The 
loss  in  weight  this  time  amounted  to  0.383  upon  the 
original  weight,  and  0.398  upon  the  first  drying,  making 
an  average  of  four  per  cent,  upon  the  bark’s  weight. 
After  this,  the  bark  was  laid  in  a  balcony  entirely  ex¬ 
posed  to  the  sun,  and  covered  with  black  shingles, 
making  it  close  and  warm,  and  after  being  allowed  to 
dry  there  for  another  hour,  there  appeared  a  loss  of 
0.459  upon  the  original  weight  in  the  cool  store,  and 
0.481,  when  compared  with  the  sun-dried  weight,  being 
on  the  average  a  loss  of  5  per  cent. 

The  above  figures  will  correspond  to  most  cases.  If 
the  smooth  bark  is  taken  out  of  a  cool  store  and  allowed 
to  remain  in  the  sun  during  a  few  hours,  or  if  it  is  left 
in  the  forest  over  night,  and  not  upon  the  earth  where 
the  dew  may  moisten  it,  but  upon  trestles  elevated 
about  a  foot  from  the  ground,  it  will  lose  about  2  per 
cent  of  its  weight  in  the  first  event,  and  become  heavier 
in  the  latter.  The  difference  will  be  greater,  perhaps  4 


96 


CHEMISTRY  OF  TANNING. 


or  5  per  cent.,  if  the  bark  is  exposed  to  a  stronger  or 
longer-continued  sun  heat,  or  if  it  is  allowed  to  remain 
on  the  low  ground,  or  upon  staves,  as  happens  when 
bark  is  peeled  in  fine  summer  weather,  and  the  binding 
together  of  the  bundles  deferred  until  evening. 

We  consider  it  obvious  that  if  the  sun-dried  bark  is 
allowed  to  lie  carelessly  upon  the  ground  where  the  dew 
has  fallen,  greater  fluctuations,  impossible  to  calculate 
in  advance,  may  be  the  result. 


CHAPTER  XIII. 

PLANTS  CONTAINING  TANNIN  USED  AS  SUBSTITUTES 
FOR  OAK  BARK* 

Owing  to  the  great  lack  of  tanning  materials  which 
was  felt  several  years  back,  and  which  gave  rise  to  a 
multitude  of  experiments  with  native  and  foreign  sub¬ 
stances  containing  tannin  as  a  substitute  for  oak  bark, 
the  general  committee  of  the  Bavarian  Agricultural 
Society  of  Munich  instituted  a  careful  testing  of  those 
plants  which  seemed  most  adapted  to  supply  this  defi¬ 
ciency.  The  Gemeinnutzige  Wochenschrift  (No.  42), 
published  at  Wartzburg,  contains  the  principal  agri¬ 
cultural  and  chemical  experiments  there  made,  and  we 
extract  from  it  all  which  have  reference  to  oak  bark 
and  its  substitutes. 

Plants  which  are  intended  to  yield  a  substitute  for 
oak  bark  must  be  susceptible  of  cultivation  in  large 
quantities,  and  the  cost  of  cultivation  and  product 
should  stand  in  such  a  proportion  to  the  price  offered 
by  tanners  that  its  culture  may  remunerate  the  farmer. 
To  this  end  three  species  of  plants,  the  common  snake- 
root,  or  adder's  wort,  the  tormentil  and  the  turmeric  (but 
at  first  only  the  two  first)  were  tested  as  to  their  culti¬ 
vation  and  tanning  properties. 

The  snakeroot  cannot  be  well  propagated  from  seeds, 
as  many  of  these  remain  unripe  or  do  not  bud,  and  the 


*  Gemeinnutzige  Wochenschrift. 


PLANTS  CONTAINING  TANNIN. 


97 


ripe  ones  need  from  two  to  three  years  before  they  ger¬ 
minate,  which  is  a  great  drawback.  Therefore,  it  is 
necessary  to  take  old  roots  and  sprouts,  cut  them  up 
with  the  seed  capsules  and  lay  them  in  furrows  as  po¬ 
tatoes  are  planted.  This  plant  always  requires  a  moist 
soil,  and  can  only  be  cultivated  in  ground  suited  to  it; 
in  clay  or  sandy  soil  it  does  not  thrive  at  all.  At  Munich 
a  lot  of  moist  ground  produced  the  following  in  one 
day’s  gathering:  16  cwt.  of  roots,  16  cwt.  of  leaves, 
and  8  cwt.  of  refuse,  which  together  contained  4  cwt. 
80  lbs.  of  tannin  material,  or  12  per  cent,  of  the  gross 
product,  while  the  bark  of  oak  saplings  yields  15  per 
cent.  Fraas  reckons  the  net  product  per  day’s  work, 
after  deducting  the  cost  of  culture  at  about  $4,  which 
does  not  seem  very  tempting  when  we  contrast  it  with 
potatoes,  and  consider  the  risk  of  sale. 

The  tanning  experiments  made  with  snakeroot,  by 
Mr.  Streicher,  a  tanner  of  Munich,  give  the  following 
results  as  compared  with  tanning  made  with  oak  and 
hemlock  barks.  A  slower  tanning,  a  pale  color,  a 
lesser  weight,  and  less  firmness  in  the  leather.  One 
great  disadvantage  of  this  root  in  tanning,  is  the  great 
quantity  of  starch  flour  that  it  contains,  which  forms  a 
pasty  sort  of  slime  upon  the  hides  which  prevents  the 
tannin  from  penetrating  thoroughly.  These  experi¬ 
ments  were  made  with  roots  of  the  crop  of  1859.  In 
1860  the  product  of  the  crop  was  handed  over  to  Mr. 
Kester,  superintendent  of  factories  at  Munich,  who 
made  experiments  similar  in  result  to  those  of  Mr. 
Streicher. 

The  tormentil  grows  everywhere,  in  meadows,  heaths, 
and  in  light  wooded  grounds.  Its  roots  form  a  hard 
tubercle  varying  in  bulk  from  the  size  of  a  hazel-nut  to 
that  of  a  chestnut,  having  leaves  similar  to  those  of  the 
strawberry  plant,  and  the  same  sort  of  blossom,  only  of 
a  yellow  color.  It  contains  about  16  per  cent,  of  tan¬ 
ning  material.  The  seeds  are  generally  barren,  and 
even  when  they  germinate  they  require  at  the  least  two 
years’  time  to  form  a  bulb  of  the  size  of  a  hazel-nut ; 
moreover,  they  need  a  moist  soil,  and  one  enriched  by 
7 


98 


CHEMISTRY  OF  TANNING. 


decayed  vegetable  matter,  a  requirement  which  cannot 
be  filled  except  by  breaking  up  meadows  or  moor  lands. 
They  can  be  raised  like  potatoes  from  root  eyes;  but 
these  eyes  require  three  years  before  they  come  to  a 
serviceable  bulb,  and  moreover  they  are  very  difficult  to 
cut  off  even  with  a  sharp  knife. 

This  will  be  sufficient  to  make  it  understood  that  this 
plant  cannot  be  compared  with  the  easily  cultivated 
barks  of  the  oak  and  fir.  Reckoning  the  percentage 
according  to  the  table,  it  takes  only  123£  parts  of  young 
oak  bark  to  effect  the  same  results,  for  which  tormentil 
root  requires  845 i  parts,  or  seven  times  as  much  of  the 
latter  to  reach  a  like  degree  in  .the  fermentation  of  the 
leather.  Fraas,  on  his  side,  reckons  that  dry  tormentil 
roots  could  be  sold  at  $1.25  per  cwt. ;  but  he  doubts 
whether  the  grainer  could  produce  it  for  that  price.  In 
addition  to  this  Mr.  Kester  remarks  that  the  leather 
tanned  with  tormentil  is  inferior  in  quality  to  that 
tanned  with  oak  bark. 

These  interesting  experiments,  although  they  turned 
out  negatively,  are  followed  by  still  more  instructive 
experiments  upon  the  produce  and  tanning  contents  of 
the  oak  bark  forests,  in  the  palatinate  and  in  central 
Franconia,  facilities  for  the  same  having  been  accorded 
to  the  superintendent,  Dr.  Fraas,  by  the  royal  minister 
of  woods  and  forests.  This  bark  came  from  the  forest 
districts  of  Ammer,  Pirmaseus,  Twerbriicken,  Laute- 
recken,  and  Spier.  Dr.  Fraas  tested  the  quality  of  tan¬ 
ning  material  therein  contained,  according  to  Muller’s 
method ;  and  in  connection  with  their  soil,  age,  time  of 
stripping,  etc.  The  following  deductions  are  drawn : — 

1st.  The  bark  of  oak  grown  in  a  sandy  soil  indicates 
everywhere  a  small  content  of  tanning  material  (6  to  8 
per  cent.),  especially  in  the  forest  districts  of  Twer- 
briicken  and  Ammer.  The  adjoining  districts  not  only 
offer  a  poor  sandy  bottom  of  mottled  sandstone,  but 
they  are  situated  at  the  highest  point  of  land  above  the 
level  of  the  sea  in  the  palatinate. 

2d.  Trees  grown  on  moorland  are  very  rich  in  tan- 


PLANTS  CONTAINING  TANNIN. 


99 


ning  material,  containing  about  21  per  cent,  at  the  age 
of  twenty-two. 

3d.  Bark  twenty  years  old  is  quite  as  rich,  and  still 
mo^e  tannin  is  obtained  from  that  grown  in  a  clay  soil. 
The  rich  bark  grown  in  the  district  of  Schafferstadt  is 
aided  by  the  mild  climate,  and  owing  to  the  vicinity  of 
the  Rhine,  by  an  underground  dampness  together  with 
a  deposit  of  the  best  old  Rhine  soil. 

4th.  Roll  barks  from  trees  twelve  to  twenty-three 
years  old  is  richer  in  tanning  material  than  the  bark  of 
twigs  and  branches. 

5th.  The  middle  part  of  good  sized  trunks  contains 
more  tannin  stutf  than  the  top  or  the  lower  part  in 
trees  from  eighteen  to  twenty-two  years  old ;  but  in 
trees  ten  years  of  age  the  top  is  the  richest  part. 

6th.  A  mixture  of  the  two  seems  advantageous  to 
improve  the  tanning  material. 

7  th.  Barks,  stripped  from  trees  ten  to  sixteen  years 
old,  contained  from  11  to  ll?  per  cent,  of  tanning  ma¬ 
terial ;  from  twenty  to  twenty-five  years,  12  per  cent.; 
and  from  thirty  to  forty  years,  11|  per  cent.  Excep¬ 
tion  to  this  occurs  from  causes  relating  to  climate  and 
the  condition  of  the  soil. 

8th.  The  amount  of  tanning  material  contained  in 
bark,  stripped  off  in  the  spring,  is  much  greater  than 
when  it  is  peeled  in  summer  and  in  autumn. 

9th.  The  quantity  of  tannin  held  in  young  firs,  grown 
in  Central  Franconia,  is  considerable,  and  the  quality 
very  good. 

10th.  The  tanning  material  of  young  oak  bark  is  so 
excellent  in  its  effects  that  it  cannot  be  equalled  by  any 
other  sort  of  tanning  material,  and  in  nowise  by  snake- 
root  or  tormentil  root. 

To  this  we  shall  add  that  bark  oak  is  sold  at  a  higher 
price  per  cord  than  that  peeled,  because  the  heat  given 
by  it  is  quite  equal  to  that  of  beech  wood,  and  the  char¬ 
coal  produced  by  it  is  even  preferred,  in  the  foundries 
there,  to  the  charcoal  made  from  beech  wood.  , 

Barked  oak  burns  in  a  dry  state  without  crackling 
like  birch  wood ;  so  that  what  it  lost  in  the  volume  of 


100 


CHEMISTRY  OF  TANNING. 


the  cord  by  peeling  off  the  bark,  is  made  up  by  the  high 
price  obtained.  Therefore  in  places  where  they  grow 
cultivated  oak  bark  forests  are  most  profitable.  But 
tan  bark  containing  8  per  cent,  of  tanning  material,  by 
comparison  with  tan  bark  containing  12  per  cent.,  is 
not  one-third  less  in  value,  but  one-half,  because  the 
cost  of  production  and  the  tanning  manipulations  ren¬ 
der  this  product  disproportionally  dearer,  and  still  the 
heavier  loses  less  in  weight.  The  tanner’s  test  of  tan 
bark  is  the  weight  of  his  hides  and  the  time  taken  to 
tan  them,  for  time  lost  is  money  lost. 

Mr.  Briigl,  of  Ipsheim  (Central  Franconia),  has  com¬ 
piled  a  most  admirable  work,  giving  fully  the  cost  of 
procuring  and  a  calculation  of  the  return  upon  bark 
peeled  in  the  oak  and  pine  forests  of  his  district.  We 
are  not  able  at  present  to  give  a  comprehensive  extract 
from  this  admirable  book,  which  is  well  worthy  of 
perusal. 

1st.  One  hundred  well-grown,  fine-conditioned  oak 
trunks,  16  feet  long  and  1  h  thick  were  stripped,  and  the 
difference  in  the  net  proceeds  amounted  to  28  cents 
higher  than  for  one  hundred  unpeeled. 

2d.  One  hundred  trunks  12  feet  long  and  one  thick 
were  peeled  and  yielded  9  cents  more. 

3d.  A  cord  of  oak  wood  was  stripped  and  lost  ^  of 
the  cord  measurement,  despite  which,  counting  the  value 
of  the  tan  bark,  $1.58  more  per  cord  was  obtained. 

4th.  One  hundred  fagots  after  being  peeled  showed  a 
loss  in  the  cord  size  of  28  per  cent.,  and  yielded,  count¬ 
ing  the  value  of  the  tan  bark,  an  increase  of  $1.53. 

5th.  Even  4  to  5  inches  thick  saplings  yielded,  when 
barked,  an  advance  of  $1.08  when  compared  with  un¬ 
barked. 

6th.  Sixteen  hemlock  trunks,  14  to  36  feet  in  length, 
and  3  to  6  feet  in  thickness,  between  50  and  60  years 
of  age,  were  peeled ;  they  yielded,  counting  the  value 
of  the  tan  bark,  in  advance  of  27  cents.  The  days’ 
work  will  yield,  according  to  this  calculation,  of  greater 
profit,  about  $3.25. 


METHODS  OF  ESTIMATING  THE  TANNING  POWERS.  101 


CHAPTER  XIV. 

METHODS  OF  ESTIMATING  THE  TANNING  POWER  OF 
ASTRINGENT  SUBSTANCES. 

EXAMINATION  OF  BARKS — CHEMICAL  EXAMINATION — R.  WARRINGTON’S 
PROCESS — DAVY’S  PROCESS— BELL  STEPHENS’S  PROCESS — MULLER’S 
PROCESS — TANNIN  CONTAINED  IN  THE  PRINCIPAL  ASTRINGENT  MAT¬ 
TERS — RESPECTIVE  QUANTITIES  OF  TANNING  SUBSTANCES  NECESSARY 
TO  TAN  AN  EQUAL  QUANTITY  OF  LEATHER — MODE  OF  ASCERTAINING 
THE  RICHNESS  IN  TANNIN  OR  VALUE  OF  BARKS. 

The  means  of  ascertaining  the  value  of  barks  are  of 
two  kinds:  1st.  By  inspection  of  the  bark.  2d.  By 
chemical  analysis.  This  last  method  is  the  best  and 
surest. 

EXAMINATION  OF  BARKS. 

A  good  bark  is  known  by  its  color.  The  most  highly 
esteemed  is  that  which  is  white  outside  and  reddish  in¬ 
side,  rough  and  dry  on  the  side  of  the  wood,  breaks 
easily  and  gives  less  ligneous  matter ;  the  taste  is  the 
most  astringent  with  a  strong  smell  principally  when 
ground.  A  sign  of  bad  quality  is  when  the  epidermis 
and  cortex  are  very  thick  and  have  a  blackish  color ; 
then  the  bark  is  too  old  and  has  experienced  a  beginning 
of  decomposition.  It  is  the  same  with  that  which  has 
been  left  exposed  a  long  time  to  the  rain.  The  bark 
which  is  red  inside  has  lost  its  odor,  and  that  which  is 
dirty  has  lost  a  part  of  its  property. 

CHEMICAL  EXAMINATION. 

We  have  said  that  barks  contained  tannin,  gallic  acid, 
extractive,  etc.,  and  that  they  were  more  valuable  for 
tanning  in  proportion  as  they  contain  more  tannin.  It 
is  evident  then  that  by  chemically  isolating  this  princi¬ 
ple,  and  determining  the  proportions  we  could  ascertain 
the  value  of  a  bark.  One  of  the  characteristics  of  the 
tannin  is  to  form  with  gelatine  an  insoluble  compound. 
It  is  then  sufficient  to  ascertain  the  value  of  a  bark  to 
take  the  amount  in  weight  of  the  precipitate  obtained 


102 


CHEMISTRY  OF  TANNING. 


of  equal  weights  of  these  substances  put  in  infusion 
into  water,  and  precipitate  by  gelatine.  These  precipi¬ 
tates  filtered  and  dried  give  by  their  weights  the  propor¬ 
tion  of  tannin.  We  give  below  the  different  processes: 

R.  Warrington’s  Process. — This  chemist  speaks 
thus:*  “Having  often  occasion  to  examine  the  value  of 
astringent  substances  used  by  tanners,  I  think  it  will  be 
interesting  for  the  trade  to  know  my  method  of  operating. 

“I  have  chosen  gelatine  as  the  basis  of  the  determi¬ 
nation  of  the  value  of  astringent  substances,  and  after 
many  trials  with  several  kinds  of  gelatine,  I  have  found 
that  isinglass  of  the  best  quality  was  the  most  proper 
for  those  assays.  It  is  with  isinglass  that  I  prepared 
the  proof  liquor  of  a  quantity  such  that  each  division 
of  a  graduated  tube  is  equivalent  to  0  gramme  001  of 
pure  tannin.  A  given  weight  of  the  substance  was 
treated  by  water,  and  the  clear  liquor  was  precipitated 
by  the  proof  liquor  till  no  more  precipitation  was  formed. 

“  It  is  necessary  during  the  operation  to  try  from  time 
to  time  a  portion  of  the  solution  to  be  sure  of  the  pro¬ 
gress  of  the  analysis.  This  operation,  on  account  of  the 
nature  of  the  precipitate,  has  presented  some  difficulties. 
It  Avas  impossible  to  filter;  then  I  adopted  the  folloAving 
plan: — 

“I  took  a  glass  tube  about  1  foot  long  and  i  an  inch 
in  diameter  and  introduced  into  it  a  little  piece  of  a 
damp  sponge  that  I  fixed  loosely  at  the  inside  end. 
When  I  desire  to  extract  a  portion  of  the  liquor  sub¬ 
mitted  to  the  proof  for  a  particular  essay,  I  immerse  a 
few  seconds  this  tube  in  the  precipitated  solution.  The 
clear  liquor  filters  by  ascension  through  the  sponge  in 
the  tube,  and  is  decanted  into  another  glass;  if  by  add¬ 
ing  a  drop  of  the  solution  of  gelatine  a  precipitate  is 
produced,  I  pour  back  the  liquor,  and  continue  the 
operation  till  the  saturation  is  complete.  The  numbers 
of  degrees  of  the  graduate  glass  indicate  the  quantity 
of  tannin  contained  in  the  liquor.” 

Davy’s  Process. — Take  one  ounce  of  the  bark  to 


*  Memoirs  of  the  London  Chemical  Society. 


METHODS  OF  ESTIMATING  THE  TANNING  POWERS.  103 


dry,  and  reduce  it  to  a  fine  powder,  digest  it  in  a  pint 
of  boiling  water,  stirring  frequently;  after  24  hours 
filter  through  a  cloth.  Also  dissolve  one  drachm  of 
isinglass  in  one  pint  of  warm  water,  mix  equal  quanti¬ 
ties  of  these  two  liquors,  and  filter ;  the  precipitate  is 
dried  and  weighed.  The  difference  of  weights  indicates 
the  degree  of  tannin;  the  precipitate  formed  of  tannin 
and  gelatine  generally  contains  40  per  cent,  of  tannin. 

Bell  Stephens’s  Process. — Stephens,  while  studying 
Davy’s  process,  has  given  another  less  imperfect.  Mr. 
Bostwick  has  ascertained  that  the  precipitate  obtained 
by  the  gelatine  stays  in  great  part  in  suspension  in  the 
liquor,  and  is  not  separated  by  the  filter ;  in  the  second 
place,  the  proportion  of  gelatine  is  not  constant.  This 
chemist  has  ascertained  that  the  first  portions  of  gela¬ 
tine  give  a  precipitate  which  contains  50  per  cent,  of 
tannin,  while  at  the  end  it  contains  very  little.  Ste¬ 
phens  proposes  the  following  method;  Dip  for  a  few 
hours,  in  a  weak  solution  of  tanning  matter  made  with 
water  at  90°,  thin  skins  which  in  7  or  8  hours  extract 
all  the  tannin.  The  increase  in  weight  of  the  skin  in¬ 
dicates  the  quantity  of  tannin.  As  dry  skin  badly  ab¬ 
sorbs  tannin,  it  is  better  before  using  it  to  soak  it  for  ten 
minutes  in  water  at  90°  so  as  to  render  it  soft  in  all  its 
parts.  The  skin  ought  to  be  weighed  when  dried 
before  and  after  the  treatment. 

The  process  of  Davy,  while  subject  to  the  inconveni¬ 
ences  named  by  Bostwick,  is  generally  followed.  That 
of  Stephens  is  good  in  practice,  as  it  indicates  not  only 
the  strength  in  tannin,  but  also  the  appearance  of  the 
skin  after  being  tanned. 

Muller’s  Process. — Dr.  Muller  has  established  a 
method  for  the  determination  of  the  tannin  contained 
in  tanning  materials  which  justly  deserves  the  name  of 
technical  experiment;  very  satisfactory  results  are  gained 
by  it  in  a  short  time. 

The  experiment  is  based  upon  the  property  possessed 
by  tannic  acid  of  forming  with  animal  gluten  a  combi¬ 
nation  which  is  almost  entirely  insoluble  in  water  and 
which  is  called  tanat  (leather).  It  is  therefore  neces* 


104 


CHEMISTRY  OF  TANNING. 


sary  above  all  to  ascertain  how  much  of  a  solution  of 
gluten,  which  is  always  prepared  alike,  is  necessary  to 
convert  a  fixed  quantity  of  tannic  acid  into  tanat. 
After  ascertaining  this  proportion  we  have  to  find,  fur¬ 
ther,  how  much  gluten  is  necessary  to  completely  pre¬ 
cipitate  the  tannic  acid  in  a  given  tanning  material,  and 
from  these  two  proportions  we  have  a  ratio  of  which  x 
represents  the  quantity  of  tanning  material  to  be  found. 
By  means  of  a  second  proportion  we  can  very  easily 
learn  the  percentage  of  tannin  in  tanning  materials. 

Working  out  of  this  experimen  t  according  to  Muller. — 
4.38  grains  of  gluten*  are  to  be  dissolved  in  140.1 
grammes  of  water,  and  1.09  gr.  of  burnt  alum  added 
to  the  solution ;  this  addition  of  alum  effects  the  sepa¬ 
ration  of  the  tannin  from  the  gluten  in  a  much  shorter 
space  of  time  than  in  any  other  way.  With  the  solu¬ 
tion  of  gluten  thus  prepared,  the  proportions  above 
named  are  to  be  fixed:  a ,  the  weighed  part  of  the 
pure  tannic  acid  is  changed  into  tanat  by  b,  the 
weighed  part  of  the  solution  of  gluten.  Now  let  c  be 
the  weighed  part  of  the  tanning  material,  on  which 
boiling  water  is  poured  and  allowed  to  boil  for  a  time, 
when  the  water  will  turn  to  a  very  deep  brown  color. 
Then  let  it  be  carefully  poured  off  from  the  tanning 
material  into  a  glass  vessel.  Upon  the  boiled  tanning 
material  water  should  be  poured  a  second  time  and 
allowed  to  boil,  and  the  extract  then  poured  into  the 
liquor  produced  by  the  first  boiling ;  and  this  boiling 
and  adding  should  be  continued  as  long  as  the  tanning 
material  gives  any  solution ;  that  is,  as  long  as  tannic 
acid  is  produced,  which  can  be  ascertained  by  the  brown 
color  of  the  boiling  water.  When  the  water  remains 
colorless  after  long  boiling,  then  the  dyestuff  of  the 
tannic  material  may  be  known  to  be  exhausted,  and  the 
residuum,  the  boiled-out  substance,  together  with  the 
water  still  covering  it,  is  to  be  poured  into  the  solution 
of  tannic  acid  already  obtained  and  added  to  the  gluten 
after  it  is  quite  cold. 


*  This  substance  is  without  doubt  gelatine. 


METHODS  OF  ESTIMATING  THE  TANNING  POWERS.  105 


Suppose,  for  instance,  V  to  be  the  weighed  part  of 
gluten  necessary  to  decompose  all  the  tannic  acid,  then 
we  have  b  ;  b'  =  a  :  x  or  V :  b  =  x  :  a  according  as  b  is 

d  f)r 

larger  or  smaller  than  b' ;  but  in  both  cases  x  =  — r—  = 


to  the  quantity  of  tannic  acid  contained  in  c  weighed 
part  of  the  tanning  material ;  and,  therefore,  by  c : 


100  = 


a  b' 


x' — X? 


100  a  b' 
5  c 


,  which  is  the  percentage 


of  tannic  acid  contained  in  two  weighed  parts  of  tan¬ 
ning  material.  The  quantity  of  the  consumed  gluten 
will  be  fixed  by  weight.  Fill  a  glass  goblet  with  the 
solution  of  gluten  and  equipoise  it  on  a  scale,  and  add 
to  the  solution  so  weighed  the  solution  of  tannic  acid, 
as  long  as  tannic  acid  remains,  then  put  the  glass  which 
still  contains  some  solution  of  gluten  upon  the  scale 
again,  and  it  will  be  lighter  than  before  the  fixing ;  the 
additional  weight  beyond  the  equilibrium  will  give  the 
amount  of  gluten  consumed. 

In  order  to  fix  this  point  completely,  pour  some  solu¬ 
tion  of  gluten  and  pure  tannic  acid,  dissolved  in  water, 
into  watch-glasses  standing  upon  glazed  paper.  With 
two  different  splints  dip  a  drop  of  the  clear  fluid  above 
the  separated  tannic  acid,  either  into  the  solution  of 
gluten  or  the  solution  of  tannin  in  the  watch-glass  ;  the 
smallest  quantity  of  °f  unprecipitated  tannic  acid 
or  surplus  gluten  will  appear  in  the  glass  in  the  form 
of  a  white  speck,  tanat,  which  comes  up  at  the  spot 
where  dipped. 

This  experiment  may  be  made  more  accurately  and 
conveniently  by  estimating  the  quantity  of  gluten,  not 
according  to  weight  but  by  its  volume,  as  I  have  tried 
it.  Weighing  is  liable  to  error,  and  it  is  not  so  accurate 
a  plan  as  measurement.  A  vial  of  the  capacity  of  70 
cubic  centimetres  (centimetre  is  of  an  inch)  answers 
perfectly  as  a  measure ;  with  it  we  can  calculate  up  to 
0.5  centimetre,  and  regulate  the  addition  of  the  gluten, 
even  by  drops — but  it  soon  became  evident  that  this 
solution  of  gluten  was  much  too  thick  for  this  vial,  as 


106 


CHEMISTRY  OF  TANNING. 


the  narrow  month  of  the  vial  soon  became  stopped  np, 
and  owing  to  this  hindrance  in  the  work,  a  thick  solu¬ 
tion  of  gluten  does  not  precipitate  tannic  acid  nearly 
as  rapidly  as  a  thinner  and  more  freely  flowing  solution. 
I  therefore  prepared  a  solution  in  the  following  manner : 
I  dissolved  2i  grains  of  gluten  in  125  centimetres  of 
water  in  which  0.75  gr.  of  alum  had  been  previously 
dissolved.  When  the  alum  is  put  in  the  rough  into  the 
solution  of  gluten  it  dissolves  very  slowly. 

Disposition  of  a  quart  of  gluten:  0.71221  grain  of 
chemically  pure  tannic  acid  was  dried  for  such  a  length 
of  time  until  its  weight  remained  permanently  at  0.6335 ; 
then  this  quantity  was  dissolved  in  100  c.  c.  of  distilled 
water ;  of  this  solution  4  analyses  always  of  5  c.  c.  in 
goblet  glasses,  and  precipitated  with  solution  of  gluten 
prepared  in  the  manner  above  laid  down,  required  as 
follows :  5  c.  c.  tannic  acid ;  3.8  c.  c.  of  gluten ;  5  c.  c. 
ditto  ;  4.1  c.  c.  do. ;  5  c.  c.  do. ;  4.1  do. ;  5  c.  c. ;  3.5  c.  c. 
do. ;  3  minutes  were  required  to  clarify  the  liquid.  If 
we  take  the  mean  of  these  results,  it  will  appear  that  5 
c.  c.=0. 031675  grain  of  tannic  acid,  require  3.9  c.  c. 
of  gluten  in  order  to  become  converted  into  tanat.  1  c. 
c.  of  gluten  corresponds  therefore  to  0.031675;  3.9= 
0.00812  grain  of  tannic  acid. 

By  means  of  these  data  I  have  calculated  the  follow¬ 
ing  tables,  which  will  be  found  very  serviceable  in  work¬ 
ing  out,  as  they  render  all  calculations  unnecessary.  1 
c.  c.  of  gluten  corresponds  to  0.00812  grain  tannic  acid, 
therefore  2  c.  c.=0. 01624,  and  so  on;  the  quantity  of 
tannic  acid  required  for  any  quantity  of  gluten  may  be 
rapidly  ascertained  by  multiplying  0  00812  by  the  num¬ 
ber  of  c.  c.  Example :  4  grains  of  tanning  material 
would  require  75  c.  c.  of  solution  of  gluten,  therefore  4 
grains  of  tanning  material  contain  0.609  of  tannin,  for 
75  c.  c.  corresponds  to  0.609  of  tannin.  In  order  to 
reach  the  percentage,  the  following  proportion  must  be 
made : — 

4  :  100=0.609  :  x 

x=f=\ 5.225  per  cent. 

If,  in  each  experiment,  4  grains  of  tanning  material 


METHODS  OF  ESTIMATING  THE  TANNING  POWERS.  107 


are  employed,  the  per  cent,  contents  may  be  easily  ascer¬ 
tained  by  the  following  calculation.  Gluten  contained 
in  1  c.  c.  amounts  to  0.203  per  cent.,  in  2  c.  c.  to  0.406 
and  so  on,  multiplying  the  amount  consumed  in  1  c.  c. 
by  the  number  representing  the  accumulation  of  centi¬ 
metres.  With  careful  execution,  this  method  gives  re¬ 
sults  which  are  accurate  even  to  0.3,  0.5  per  cent,  as  my 
experiments  have  established. 

Special  determination  of  Aleppo  gall-nuts  of  1839. 

\st  determination :  3.6386  gr.  of  matter  required  75  c. 
c.  of  gluten,  being  equal  to  0.6090  of  tannin,  therefore 
it  contains  16.73  per  cent,  of  tannin. 

2 d  determination:  4.026  of  the  same  substance  re¬ 
quired  84.4  c.  c.  of  gluten,  being  equal  to  0.685328  of 
tannin,  therefore  it  contains  17.04  per  cent.;  the  differ¬ 
ence  amounts  to  0.31. 

Marmorina  gall-nuts  (old). — Is?  determination:  3.25675 
gr.  required  75  c.  c.  of  gluten,  being  equal  to  0.609  of 
tannin=:  18.89  per  cent. 

2 d  determination :  3.9186  of  substance  required  95  c. 
c.  of  gluten,  being  equal  to  0.77148  of  tannin,  or  19.60 
per  cent. 

Chinese  gall-nuts. — Is?  determination:  2.1875  gr.  of 
substance  required  62  c.  c.  of  gluten=0. 486388  of 
tannin=  22.23  per  cent. 

2d  determination :  1.6555  of  substance  required  46  c. 
c.  of  gluten=0. 37352=22. 55  per  cent. 

From  the  above  examples  the  accuracy  of  my  asser¬ 
tions  regarding  the  correctness  of  the  results  may  be 
seen.  0.5,  0.3  per  cent,  is  the  error. 

Method  of  Dr.  D.  W.  Gerland. — We  extract  from 
the  London  Chemical  News  the  following  process,  which 
we  think  very  reliable.  The  importance  of  a  sure  and 
an  easy  method  for  the  estimation  of  tannic  acid  as  a 
means  of  determining  the  value  of  tanning  materials, 
has  been  duly  noticed,  and  a  great  number  of  processes 
described  for  that  purpose.  An  examination  of  these 
methods,  induced  by  numerous  samples  sent  to  me  for 
analysis,  has  convinced  me  that  those  recommended  fail 
in  answering  the  desired  end,  as  some  yield  too  high  a 


108 


CHEMISTRY  OF  TANNING. 


percentage  of  tannic  acid  by  the  accompanying  gallic 
acid  being  estimated  as  tannic  acid,  some  giving  alto¬ 
gether  incorrect  results,  while  others  are  too  compli¬ 
cated  to  be  of  service  to  any  but  the  skilled  chemist. 

After  a  long  experience  I  have  found  that  the  estima¬ 
tion  of  tannic  acid  is  accomplished  with  great  accuracy 
and  speed,  as  tannate  of  antimony  precipitated  by  a 
standard  solution  of  tartar  of  antimony,  if  the  opera¬ 
tion  is  conducted  in  the  following  manner: — 

The  solution  of  tartar  emetic  I  prefer  of  such  strength 
that  1  c.  c.  will  precipitate  0.005  gramme  tannic  acid. 
One  equivalent  of  tartar  emetic  dried  at  212°, 

=  KO,SbO3,C8H4O,0=332.2 
requires  three  equivalents  of  tannic  acid, 

3(C18H8012)=636 

to  form  one  equivalent  of  tannate  of  antimony — 
Sb03,3(C18H8C012)=789. 

Accordingly,  0.002611  gramme  of  tarter  emetic  will 
precipitate  0.005  of  tannic  acid  of  galls,  and,  therefore, 
2.611  grammes  tartar  emetic  dried  at  212°  are  dissolved 
in  1000  c.  c.  of  water,  each  c.  c.  of  which  solution  is 
then  equal  to  0.005  gramme  of  tannic  acid.  This 
liquor  added  to  a  dilute  solution  of  tannic  acid  produces 
no  change,  but  if  a  solution  of  chloride  of  ammonium 
is  mixed  with  the  latter,  the  tannate  of  antimony  ap¬ 
pears  as  a  thick,  curdy  precipitate,  which,  after  stirring, 
settles  readily,  leaving  the  supernatant  solution  perfectly 
clear,  so  that  it  is  easy  to  perceive  whether  another 
drop  of  the  antimonial  liquor  will  again  cause  a  precipi¬ 
tate.  Its  voluminous  and  opaque  character  makes  it 
very  perceptible  to  the  last,  so  that  I  found  less  difficulty 
in  observing  the  end  of  this  reaction,  than  with  the 
usual  estimation  of  sulphuric  acid  by  a  standard  solu¬ 
tion  of  chloride  of  barium.  If  as  much  and  more  of 
the  tartar  solution  has  been  added  as  will  cause  a  pre¬ 
cipitate  in  the  sample,  the  filtrate  of  the  same  will  be 
found  free  from  both  antimony  and  tannic  acid,  and  the 


METHODS  OF  ESTIMATING  THE  TANNING  POWERS.  109 

precipitate,  after  filtering,  washing,  and  drying  at  112,° 
consists  of  pure  tannate  of  antimony  represented  by — 

Sb03,3(C18H8012), 

and  contains  all  the  tannic  acid  of  the  original  liquor. 
Any  gallic  acid  that  might  have  been  present  in  the  tan¬ 
nic  acid  is  not  precipitated  under  these  circumstances, 
and  consequently  does  not  interfere  with  the  estimation 
of  tannic  acid;  for  the  ammonia  salt,  whilst  it  renders 
the  tannate  of  antimony  insoluble,  keeps  the  gallic  acid 
in  solution.  Nor  do  the  coloring  matter  and  other  im¬ 
purities,  extracted  by  water  from  the  tanning  materials, 
affect  this  process.  It  is,  however,  to  be  observed  that 
the  reaction  of  the  liquor  is  neutral  or  slightly  acid. 
The  number  of  c.  c.  of  the  standard  solution  used  will, 
therefore,  when  multiplied  by  0.005,  give  the  exact 
amount  of  tannic  acid  in  the  sample,  or  the  percentage, 
if  0.5  gramme  were  employed. 

To  illustrate  the  exactness  of  the  method  I  add  a  few 
of  my  experiments.  No.  1.  0.5  gramme  of  commercial 
tannic  acid  of  galls  was  dissolved  in  100  c.  c.  of  water, 
of  which  30  c.  c.  were  mixed  with  a  solution  of  chloride 
of  ammonium  and  diluted  with  water  to  about  200  c.  c. 
After  having  added  29.1  c.  c.  of  the  standard  solution, 
the  filtered  liquor  was  free  from  tannic  acid,  showed  a 
slight  reaction  of  antimony,  and  contained  gallic  acid. 
The  precipitate  thrown  on  a  weighed  filter,  and  after 
washing  with  water  and  dried,  weighed  0.1791,  and  was 
found  to  contain  18.01  per  cent,  of  oxide  of  antimony; 
the  formula — 

Sb03,3(C18H8013), 

requires  18.12  percent.  The  sample, therefore,  contained, 
according  to  the  quantity  of  standard  solution  used,  97 
per  cent,  of  tannic  acid ;  calculated  from  the  amount  of 
precipitated  tannate  of  antimony,  96.24  per  cent,  of  tan¬ 
nic  acid. 

No.  2.  10  grammes  of  oak  bark  are  exhausted  with  hot 
water,  the  filtered  solution  diluted  to  300  c.  c.,  of  which 
50  c.  c.  were  treated  as  above.  The  amount  of  standard 
solution  used  was  12.51  c.  c. ;  the  weight  of  the  dried 


110 


CIIEMISTRY  OF  TANNING. 


precipitate  was  0.1563  gramme,  containing,  according  to 
calculation,  0.1257  gramme  of  tannic  acid.  The  oxide 
of  antimony  in  the  precipitate  was  equal  to  18.07  per  cent. 

No.  3.  Dried  valonia  extract  was  treated  in  the  same 
manner.  0.5  gramme  required  38.8  c.  c.  of  antimonial 
solution;  the  percentage  of  tannic  acid  was  38.92. 

It  would  be  an  interesting  experiment  to  try  the 
tanning  strength  of  barks  of  different  kinds  and  varieties 
of  every  country  during  the  four  seasons  of  the  year  at 
different  ages;  and  it  would  be  more  interesting  to 
analyze  at  the  same  time  the  roots,  trunks,  branches, 
leaves,  etc. 

We  give  below  a  table  of  the  quantities  of  tannin 
contained  in  the  principal  tanning  substances. 


Substances.  Percentage  of  Tannin.  Authority. 

Catechu,  Bombay  . 

55.00 

Davy. 

Bengal 

44  00 

It 

“  Bombay,  light  color  . 

26.32 

Mulligan. 

“  Pegu,  dark  brown 

color 

46.88 

a 

Rhatany  root  .... 

it 

42.60 

Peschier. 

38.30 

C.  G.  Gmelin. 

Kino  .... 

15.00 

Yauquelin. 

Butea  gum  .... 

73.20 

E.  Solly. 

Nutgalls,  Aleppo  . 

65.00 

Guibourt. 

“  Chinese  . 

69.00 

Bley. 

“  Istrian 

24.00 

Roder. 

Oak,  old  white,  inner  bark 

21.00 

Cadet  de  Gassincourt. 

ll  It  ll  ti  it 

14.20 

Davy. 

“  young  “  “  “ 

15.20 

U 

“  “  colored  or  middle 

bark  . 

4.00 

ll 

“  “  entire  bark 

6.00 

Davy  &  Geiger. 

“  “  spring-cut  bark 

22.00 

Davy. 

“  Kermes,  bark  of  the  root  . 

8.90 

•  ll 

“  100  years  old  . 

8.45 

G.  Muller. 

“  young  .... 

13.87 

ll 

“  British,  50  years  old 

8.90 

Mulligan  &  Downing. 

“  “  about  50  years 

9.76 

ll  ll 

It  It  ll 

6.12 

It  ll 

“  Southampton,  about  50  . 

8.80 

ll  ll 

“  Coppice  .... 

12  55 

It  It 

“  Irish,  45  years  old  . 

9.50 

ll  ll 

“  Belgian,  popering 
“  “  heavy . 

8.33 

ll  ll 

10.74 

ll  ll 

“  “  light  . 

8.52 

ll  It 

METHODS  OF  ESTIMATING  THE  TANNING  POWERS.  Ill 


Oak,  Eschurgh 

19  35 

Gl.  Muller. 

Divi  divi  .... 

29.80 

Mulligan  &  Downing. 

i  l 

49.25 

Gf.  Muller. 

Yalonia.,  Smyrna 

34.18 

Mulligan  &  Downing. 

Myrobalans  .... 

20.91 

Mulligan  &  Downing. 

Mimosa  bark  .... 

11.81 

i  t  It 

a 

31.16 

G.  Muller. 

Terra  Japonica 

44.00 

Esenbeik. 

Avens  root  .... 

41.00 

Tromsdorff. 

Squill,  bulb  .... 

24.00 

Vogel. 

Statice  ..... 

12.40 

Parrish. 

Birch  bark  .... 

1.60 

Davy. 

it 

1.40 

Biggers. 

Beech  bark  .... 

2.00 

Davy. 

Larch  “  . 

1.60 

Davy. 

it  (t 

35.10 

Mulligan  &  Downing. 

Caratree  bark 

12.16 

ti  it 

Hemlock  “  . 

13.92 

i(  it 

Hazel  “  . 

3.00 

Davy. 

Chestnut,  American  jose 
“  Carolina  . 

8.00 

Cadet  de  Gassincourt. 

6.00 

“ 

“  French 

4.00 

J.  de  Fontenelle. 

“  Spanish,  white  inner 

bark 

1.30 

Davy. 

1 1 

“  Spanish,  colored  bark 

0.30 

“  “  entire  “ 

0.50 

t  i 

“  horse 

2.00 

J.  de  Fontenelle. 

Poplar,  Lombardy  . 

3.50 

ti 

Black  thorn  .... 

3  30 

Davy. 

ti 

Ash  bark  .... 

3.30 

Sassafras  .... 

58.00 

Reinsch. 

Elm  . 

2.90 

Davy. 

<  t 

Sumach,  Sicily 

16  20 

“  Malaga 

16.40 

i  t 

ft  it 

10.40 

Franck. 

“  Carolina  . 

5.00 

Cadet  de  Gassincourt. 

“  Virginia  . 

10.00 

ti 

tt 

19.35 

G.  Muller. 

“  Palermo  . 

24.31 

Mulligan  &  Downing. 

Willow,  Leicester,  white  inner  „ 

bark 

16.00 

Davy. 

“  colored,  middle  bark  . 

3.10 

i  t 

“  entire  bark 

6.80 

(( 

tt  it 

3.95 

Mulligan  &  Downing. 

“  bark  of  the  trunk 

1.40 

Biggers. 

“  weeping  . 

16.00 

Cadet  de  Gassincourt. 

Sycamore  bark 

16.00 

ti 

t  t 

1.40 

Biggers.' 

Eder  . 

2  30 

Davy. 

Plum  tree  .... 

1.60 

Biggers. 

112 


CHEMISTRY  OF  TANNING. 


Cherry  tree  .... 

24.00 

Cadet  de  Gassincourt. 

“  Cornish  . 

19.00 

ii 

Tormentil  root 

46.00 

ii 

Cornus  sanguinea  of  Canada  . 

44.00 

U 

Alder  bark  .... 

36  00 

ii 

Apricot  bark  .... 

32.00 

it 

Pomegranate  bark  . 

32.00 

ii 

Bohemian  olive 

14.00 

if 

Tan  shrub  with  myrtle  leaves  . 

13  00 

if 

Service  tree  bark 

18.00 

if 

Cloves  ..... 

15.00 

Davy. 

Winter  bark  .... 

9.00 

Henry. 

Comparative  Quantities  of  Different  Tannine/  Substances 
Necessary  to  tan  an  Equal  Quantity  of  Leather. 

Davy,  who  made  a  series  of  experiments  of  the  highest 
interest,  ascertained  that  Catechu  is  the  most  energetic 
substance  for  tanning.  According  to  this  chemist  one 
pound  of  Catechu  is  equivalent  to 


Niitgalls  .  .  .  .  .  . '  21  lbs. 

Sumach  .  .  .  .  .  .  .  3  “ 

Willow  lark  .  .  .  .  .  .  7$  “ 

Oak  ........  8  “ 

Horse-chestnut  .  .  .  .  .  .  11  “ 

Elm . 18  “ 

Ordinary  willow  .  .  .  .  21  “ 


In  treating  of  extracts,  we  shall  indicate  the  proper¬ 
ties  of  a  new  preparation  of  oak  bark  which  unites  all 
the  properties  both  of  oak  and  catechu. 


CHAPTER  XY. 

TAN,  OR  POWDERED  OAK-BARK. 

The  more  finely  divided  a  substance,  the  sooner  and 
more  readily  does  it  yield  to  the  action  of  the  liquid 
which  dissolves  its  constituents.  Water,  accordingly, 
dissolves  the  tannin  from  bark  in  powder  much  more 
readily  than  from  the  bark  in  coarse  pieces.  The  grind¬ 
ing  of  the  bark  for  tanning  purposes  is,  therefore,  indis¬ 
pensable.  It  must  not,  however,  be  reduced  to  impal¬ 
pable  fineness,  else  the  solvent  will  act  upon  it  too  rapidly. 
Very  fine  powders  also  form  a  compact  mass  when  wet, 


TAN,  OR  POWDERED  OAK  BARKS. 


113 


and  thus  obstruct  or  retard  the  infiltration  of  the  solvent 
liquid. 

Bark  is  ground  in  mills  varying  in  construction  in 
different  countries,  and  driven  or  propelled  by  horse, 
water,  or  steam  power.  In  England,  it  is  crushed  be¬ 
tween  chasers,  or  stones.  There  is  a  mill  of  ingenious 
construction  used  in  Salleron’s  tannery  in  France,  but  as 
its  rapid  motion  so  modifies  the  bark  as  to  cause  it  to 
impart  color  to  the  hides,  we  omit  a  description  of  it. 

In  the  South  of  France  they  use  a  vertical  mill  of 
hard  stone,  similar  to  that  employed  for  crushing  oil 
seeds.  It  consists  of  two  vertical  stones  (Fig.  2),  of 
about  7 3  feet  in  diameter,  and  18  inches  in  thickness. 
The  axle  of  these  stones  is  fixed  in  a  frame  which  in¬ 
closes  an  upright  shaft  turning  upon  a  pivot,  and  fixed 
in  the  centre  of  a  strong  stone  bed.  Rotary  motion 
being  communicated,  imparts  to  each  stone  a  double 
movement ;  that  ftpon  the  other,  and  that  which  it  under¬ 
goes  in  describing  a  circle  upon  the  stone  bed  upon  which 
it  rolls. 


Fig.  2. 


The  axle  of  each  stone  should  be  so  adjusted  as  to 
allow  it  to  be  raised  or  lowered  according  to  circum¬ 
stances.  One  of  the  stones  is  placed  nearer  to  the 
vertical  shaft  than  the  other,  so  as  to  give  a  greater 
8 


114 


CHEMISTRY  OF  TANNING. 


extent  of  crushing  surface  beneath.  Two  followers 
press  the  bark  forward  under  the  stones,  and  a  cloth  is 
attached  to  the  outer  one,  for  the  purpose  of  rubbing 
off  any  pieces  of  bark  that  may  adhere  to  the  edges  of 
the  stones. 

Bagnall's  Machine  for  Chopping  Bark  and  Fleshing 
Hides. — Fig.  3.  General  plan  of  the  mill. 

Fig.  4.  Longitudinal  section,  showing  the  elevation 
of  a  part  of  the  machinery. 

Fig.  5.  Section  across  part  of  the  mill. 

A  (Fig.  3.  Part  of  an  undershot  wheel  moving  the 
machinery,  b.  Shaft  of  the  wheel,  giving  motion  to 


Fig.  3. 


the  bevelled  cog-wheel  c.  Another  wheel  f,  placed 
upon  a  vertical  shaft,  is  made  to  revolve  by  the  motion 
of  the  wheel  c,  and  the  cogs  upon  its  periphery  move 
the  hammer  for  beating  the  bark,  and  also  the  choppers, 
in  the  second  story  of  the  building. 

d  (Fig.  4).  A  horizontal  wheel  bevelled  upon  its  in¬ 
clined  surface,  and  toothed  in  an  epicycloidal  manner 
upon  its  periphery.  This  wheel  turns  upon  the  upper 
part  of  the  large  horizontal  shaft  E,  which  passes 
through  the  first  floor  of  the  building,  f.  Cog-wheel, 
before  referred  to,  gearing  with  the  large  bevelled 
wheel  c. 

G.  Pinion  upon  the  axle  of  the  millstone  i  (Fig.  5). 


TAN,  OR  POWDERED  OAK  BARKS. 


115 


Fig.  4. 


p.  The  beam  or  handle  of  the  cutting  blades,  moving 
upon  a  pivot,  and  made  to  rise  or  fall,  by  the  motion 
communicated  to  the  lever  N,  by  the  cogs  upon  the 
wheel  c.  When  one  of  the  cogs  becomes  disengaged 
from  the  end  of  the  lever,  the  beam  falls  by  its  own 
weight,  and  the  steel  blades  upon  its  extremity  come  in 
contact  with  and  divide  the  pieces  of  bark  placed  be¬ 
tween  them  and  similar  knives  fastened  to  the  platform 
at  i.  The  platform  i  is  made  of  strong  timbers  firmly 
secured  by  bolts  to  the  rafters  of  the  floor,  so  as  to 
enable  it  to  resist  the  shock  of  the  falling  beam.  The 
intervals  between  the  knife-blades  are  open,  so  that  the 
divided  pieces  of  bark  may  fall  through  them  into 
a  conduit  q,  from  which  they  enter  the  hopper  of  the 
mill  h,  to  be  conducted  to  the  latter  by  a  guide  j  (Fig. 
5).  The  lower  part  of  the  conduit  Q  is  provided  with 
a  wire-cloth,  which  allows  the  powder  to  fall  into  a  box 
k.  The  tan,  ground  in  the  mill,  passes  through  the 
conduit  o,  and  falls  upon  the  sieve  or  bolter  l,  its  finer 
particles  passing  through  it  into  the  trough  m  ;  those 
which  have  not  been  sufficiently  exposed  to  trituration 
being  received  upon  the  concave  mortar  or  support  s, 
and  there  reduced  to  a  state  of  fine  division,  by  the 
action  of  the  round-headed  hammer  r,  which  is  worked 
by  the  cogs  upon  the  wheel  c.  The  support  is  hollowed 
out  in  such  a  way  that,  at  each  blow  of  the  hammer,  the 
particles  of  tan  acted  upon  are  thrown  out  upon  the 
side  opposite  to  that  at  which  they  entered  it. 


116 


CHEMISTRY  OF  TANNING. 


t.  Bevelled  pinion,  in  gear  with  the  upper  surface  of 
the  wheel  d,  and  having  the  end  of  its  shaft  connected 
with  the  crank  v,  by  means  of  which  the  motion  is  com¬ 
municated  to  the  machinery  for  fleshing  the  skins.  The 


Fig.  5. 


crank  is  connected  by  means  of  the  rod  w  with  the 
lever  x,  the  end  of  which  is  perforated  with  a  number 
of  holes,  by  which  the  bar  is  so  adjusted  that  the  length 
of  the  stroke  may  be  increased  or  diminished. 

y  (Fig.  3).  Shaft  moving  upon  two  axles,  the  sockets 
of  which  are  imbedded  in  the  opposite  walls  of  the 
room ;  the  lever  y  (Fig.  4)  is  connected  with  it  near  one 
end ;  and  at  about  two-thirds  of  its  length  the  cranks 
n,  n,  are  attached,  which  gives  a  reciprocating  move¬ 
ment  to  the  branches  h ,  h,  which  support  the  fleshing- 
knives ;  so  that,  at  every  revolution  of  the  crank  v,  to 
admit  the  movement  of  which  there  is  an  opening  in 


TAN,  OR  POWDERED  OAK  BARKS. 


117 


the  ceiling  above  it,  the  branches  h ,  h,  for  fleshing  the 
skins,  are  made  to  move  in  a  transverse  direction.  In 
Fig.  4,  the  knife  for  fleshing  is  represented  at  f\  fixed 
between  two  springs  a ,  a,  which  render  it  sufficiently 
movable  to  prevent  it  from  injuring  the  skins  when 
passing  across  them.  It  is  fastened  by  its  forked  ex¬ 
tremity  to  the  branch  h  by  a  screw  and  nut,  so  that  it 
can  be  unscrewed  and  sharpened  when  necessary. 

z.  Stop  on  the  branch  h,  which  is  connected  with  the 
forked  lever  e ,  by  means  of  which  the  knife  is  made  to 
return  to  the  end  of  the  skin  without  touching  its  sur¬ 
face.  The  extremity  of  the  branch  h  rolls  upon  the 
roller  l.  By  lowering  the  handle  m,  the  knife  is  ele¬ 
vated,  while  the  skin  is  being  placed  upon  or  removed 
from  the  table,  b.  Table  or  bench  upon  which  the  skins 
are  deposited.  Each  table  is  provided  with  four  wheels 

р ,  p ,  running  in  the  grooves  </,  g,  which  maintain  it  in 
position,  and  enable  it  to  be  moved  at  will  by  the  levers 

с,  c,  so  that  each  portion  of  skin  may  be  in  turn  subjected 
to  the  action  of  the  knife. 

d.  A  spring,  pressing  upon  the  skin  near  the  edge  of 
the  table  so  as  to  prevent  it  from  changing  its  position 
under  the  fleshing-knife.  The  iron  support,  or  handle 
of  the  knife,  is  forked  or  divided,  so  as  to  receive  the 
blade  between  its  two  extremities.  The  knife  is  1 2  or 
13  inches  in  length,  and  from  3  to  5  inches  in  breadth, 
and  is  adjusted  in  the  open  part  of  the  handle,  being 
prevented  from  swerving  by  the  two  springs  a,  a. 

The  roller  l ,  with  its  forked  lever,  should  be  so  ar¬ 
ranged  that  the  knife  can  be  elevated  to  the  proper  dis¬ 
tance  from  the  table  by  pulling  the  handle  m,  and  hook¬ 
ing  it  upon  a  nail,  so  that  the  skin  may  be  removed  or 
placed  upon  the  table  without  the  necessity  of  ungear¬ 
ing  the  pinion  t  ;  the  work  being  again  commenced 
when  the  handle  is  allowed  to  rise. 

Two  benches  or  tables  are  used  in  this  apparatus,  in 
order  that  the  knife  may  be  in  operation  above  one  of 
them,  while  the  workman  is  occupied  in  adjusting  a 
fresh  skin  upon  the  other.  These  benches  should  be  as 
wide  as  the  largest  skins,  and  should  be  made  sloping  at 


118 


CHEMISTRY  OF  TANNING. 


a  slight  angle.  The  skins  are  kept  in  close  contact  with 
the  surface  of  the  support,  by  clamps  pressing  their  bor¬ 
ders  down  upon  its  edges.  The  pressure  of  the  knives 
upon  the  skin  is  regulated  by  weights  placed  upon  the 
beams  or  branches  which  support  them.  The  inventor 
does  not  confine  the  application  of  this  portion  of  the 
machinery  to  the  preparation  of  skins  for  the  tanning 
process ;  but  also  adapts  it  to  the  purposes  of  tawing 
and  to  those  of  the  currier,  by  substituting  hard  brushes 
or  other  implements  for  the  knives.  Motion  may  be 
communicated  to  the  machinery  by  the  water-wheel 
already  described,  by  a  steam-engine,  or  by  horse  power  ; 
the  labor  of  two  horses  being  sufficient  for  the  purpose. 

Weldon's  Mill  for  Grinding  Oak-Bark. —  Fig.  6,  a. 
Wooden  beam  or  cross-piece,  imbedded  in  the  walls  of 


Fig.  6. 


the  building,  and  perforated  for  the  reception  of  the 
upper  axle  of  the  main  shaft. 

b.  Iron  plate  or  socket  for  the  axle. 

c.  Axle  of  the  shaft,  the  dotted  lines  showing  its  con¬ 
nection  with  the  latter. 

d.  The  shaft,  which  may  be  square,  octagonal,  or  of 
other  suitable  form. 

e.  Lever  giving  motion  to  the  shaft  by  the  power  of 


TAN,  OR  POWDERED  OAK  BARKS. 


119 


horses  harnessed  to  the  end.  When  water  or  other 
power  is  employed,  the  lever  is  replaced  by  a  wheel 
with  the  proper  gearing. 

f.  Cylinder  forming  the  lower  part  of  the  mill.  It 
should  be  made  of  iron  or  brass,  and  may  be  either  com¬ 
pact  or  hollow,  as  shown  by  the  dotted  lines  in  the  figure. 

G.  Teeth,  or  projections  for  breaking  and  grinding  the 
bark. 

h.  Lower  teeth  for  the  same  purpose. 

i.  External  iron  or  brass  cylinder,  provided  with  simi¬ 
lar  projections  upon  its  inner  surface,  and  firmly  clamped 
and  bolted  to  the  solid  framework  Q,  which  forms  the 
base  of  the  machine. 

k.  Lower  pivot  or  axle,  firmly  united  with  the  main 
shaft,  and  turning  in  a  socket  like  the  upper  one. 

l.  ‘Iron  or  copper  socket,  fixed  in  the  cross-beam  r. 

M.  Regulating  screw  passing  through  the  nut  n,  and 

the  lower  cross-beam  t.  By  turning  it,  the  teeth  within 
the  mill  may  be  made  to  approach  or  recede  from  each 
other,  so  as  to  effect,  at  will,  a  coarser  or  finer  division 
of  the  bark. 

o.  Hopper,  made  of  strong  wood  for  receiving  ma¬ 
terials  which  are  to  be  ground. 

p.  Conical  lining  of  the  interior  of  the  mill,  also  made 
of  strong  wood.  The  whole  apparatus  is  supported  upon 
four  uprights,  Q,  Q,  firmly  imbedded  in  the  ground,  and 
held  together  by  the  cross-beams  r  and  t,  there  being 
two  at  R,  meeting  each  other  at  right  angles.  Sieves  of 
wire  are  placed  between  the  cylinder  f  and  the  floor, 
which  permit  the  passage  through  their  interstices  of 
the  fine  tan,  and  retain  that  which  is  too  coarse. 

Since  its  first  introduction,  Mr.  Weldon  has  improved 
the  construction  of  his  mill  by  making  the  teeth  mova¬ 
ble  and  by  other  changes  which  we  proceed  to  describe. 

Fig.  7.  Section  of  the  improved  mill. 

A,  a.  Hopper  for  receiving  the  bark. 

B.  Shaft  of  the  mill. 

c.  Conical  casing  of  the  cutting  surfaces,  for  feeding 
the  mill. 

d,  d.  Collar  for  staying  the  teeth,  with  four  bolts,  h . 


120 


CHEMISTRY  OF  TANNING. 


e.  Elevation  of  the  conical  part  of  the  mill  in  which 
the  teeth  are  placed. 


Fig.  7. 


G.  Section  of  the  opposite  side,  showing  the  manner 
in  which  the  teeth  are  adjusted. 

d,  d.  One  of  the  teeth  entering  the  lower  neck. 

h,  h.  Lower  collar  in  which  the  teeth  are  imbedded. 
a ,  «,  a.  Outer  cylinder,  or  cone,  cast  in  one  piece,  and 

showing  the  manner  in  which  the  movable  teeth  f,  f, 
are  adjusted. 

i,  I.  Kim  or  collar  for  the  attachment  of  the  movable 
teeth ;  a  part  of  it  is  seen  detached  in  Fig.  8. 


k,  k.  Support  of  the  interior  of  the  mill,  fastened  to 
the  outer  cone  or  cylinder  by  two  bolts,  c,  c. 


TAN,  OR  POWDERED  OAK  BARKS. 


•121 


L.  Lower  part  of  the  shaft,  turning  in  a  copper  socket 
M,  which  rests  upon  the  top  of  a  screw  by  which  the 
height  of  the  inner  part  of  the  mill  is  regulated.  Fig. 
9  exhibits  this  part,  with  the  collar  of  the  rim,  in  which 
the  socket  and  adjusting  screw  are  placed. 

Fig.  1 0.  One  of  the  movable  teeth,  detached  from  the 
exterior  of  the  mill. 

Fig.  11  is  one  of  the  teeth  from  -p.  10 

the  interior  of  the  mill. 

These  teeth  are  blades  of  iron  or 
composition-metal,  ground  to  an  edge,  and  so  placed  in 
the  mill  that  the  cutting  surfaces  are  opposed  to  each 
other,  and  inclined  in  a  direction  opposite  to  that  of  the 
revolution  of  the  shaft. 

Farcofs  Bark- Chopping  Machine. — This  machine  con¬ 
sists  of  two  feeding  cylinders  A,  A.  (Fig.  12),  which  con¬ 
vey  the  bark,  previously  spread  out  upon  an  inclined 
table  a,  to  the  edges  of  four  large  steel  blades  b  b,  which 
are  fixed  in  a  spiral  direction  upon  the  periphery  of  two 
parallel  circles,  revolving  with  the  shaft  c.  The  cylin- 


r\ 


/ 


V 


Fig.  11. 


Fig.  12. 


ders  A,  A,  are  grooved,  and  are  moved  by  cog-wheels  with 
long  teeth.  The  power,  from  whatever  source,  is  trans¬ 
mitted  at  the  same  time  to  these  wheels,  and  to  the 
bladed  circles ;  b  is  a  steel  tie-piece,  which  supports  the 
pieces  of  bark  when  exposed  to  the  action  of  the  knives, 


122 


CHEMISTRY  OF  TANNING. 


each  of  the  latter  passing  over  it,  like  one  blade  of  a 
pair  of  shears  over  the  other. 

The  levers  f  suspend  the  weight  G,  the  object  of  which 
is  to  bear  upon  the  shaft  of  the  cylinder  A,  which  is 
constantly  elevated  by  the  passage  of  the  bark  beneath 
it.  Guides  are  so  placed  as  to  direct  these  levers  in 
their  vertical  movements,  and  the  bark  is  prevented,  by 
guards  or  side  pieces,  from  falling  out  of  the  grooves, 
over  the  sides  of  the  cylinders.  The  feeding  cylinders 
are  2  feet  2  inches  in  circumference,  and  the  relation  of 
the  pinion  of  the  wheel  c  to  the  wheel  j  which  moves 
it,  is  that  of  1  to  5.  About  56  feet  of  bark  will  pass 
between  the  cylinders  in  one  minute;  in  the  same  time 
the  wheel  makes  130  revolutions,  and  as  it  is  armed  with 
4  blades,  the  bark  is  cut  into  520  pieces,  each  one  nearly 
1  y3q th  inches  in  length.  More  than  1600  pounds  of 


Fig.  13. 


bark  can  be  chopped  in  an  hour  with  this  machine, 
when  in  good  order  and  properly  worked.  Some  are 
made,  with  which  one  man  can  work  up  daily  more  than 
3000  pounds. 


TAN,  OR  POWDERED  OAK  BARKS. 


123 


Fig.  13  is  the  plan  in  elevation. 
Fig.  14  is  the  ground  plan. 

Fig.  14. 


Fig.  15  shows  the  axle-pin  of  the  bladed  cylinder; 
and  Fig.  16  is  an  end  view  of  the  latter. 


Fig.  15.  Fig.  16. 


Fig.  17  represents  the  cast-iron  frame  which  supports 
the  channelled  cylinders  and  bladed  cylinder. 

The  bark,  after  being  chopped  as  described  above,  is 
submitted  to  the  action  of  the  mill,  which  consists  chiefly 
of  two  parts,  the  receiving  and  the  revolving  cylinder. 
The  former  is  a  thin,  hollow  cylinder,  terminated  below 
by  a  truncated  cone,  the  interior  of  which  is  provided 
with  spiral  blades  or  teeth,  some  of  which  extend  as  far 
as  the  lower  part  of  the  cylinder.  The  base  of  the  cone 
is  attached  by  legs  to  the  cast  framework  which  supports 
the  whole  apparatus.  Above  the  cylinder  is  a  hopper, 


124 


CHEMISTRY  OF  TANNING. 


which  is  fed  from  time  to  time  with  chopped  bark,  the 
powdered  tan  falling  down  between  the  outer  cylinder 


Fig.  17. 


and  the  inner  one.  The  outer  surface  of  the  movable 
cylinder  is  provided  with  spiral  teeth,  similar  to  those  of 
the  inner  one,  and  made  of  a  wedge-shape,  so  as  to  pre¬ 
sent  a  cutting  edge  to  the  fragments  of  bark,  which  are 
first  cut  and  divided  by  the  teeth  which  extend  towards 
its  upper  part,  and  are  then  pulverized  by  those  upon 
the  two  conical  surfaces.  The  cylinder  is  made  to  re¬ 
volve  by  a  shaft  set  in  a  socket  which  is  stayed  by  a 
tie-piece.  This  latter  is  traversed  by  a  screw,  by  means 
of  which  the  nut  may  be  raised  or  lowered,  so  as  to  in¬ 
crease  or  diminish  the  space  between  it  and  the  receiving 
cylinder,  and  to  alter  at  will  the  quality  of  the  powder 
as  to  fineness  of  division.  A  bar  passes  horizontally 
across  the  interior  of  the  inner  cylinder,  and  is  firmly 
attached  to  the  shaft  passing  through  it.  The  horse 
moving  the  machinery  is  harnessed  to  an  arm  attached 
to  a  cast-iron  plate  on  the  top  of  shaft.  This  mill  is 
calculated  to  make  25  revolutions  in  a  minute,  and  is 
capable  of  grinding  8600  pounds  of  bark  in  24  hours. 

Bourgeois's  Bark  Mill. — This  machine,  which  was  in¬ 
vented  in  1841,  and  is  described  in  volume  liv.  page 
193,  of  the  French  reports  of  expired  patents,  is  used  to 
grind  bark  by  means  of  two  cylinders,  one  of  which 
(Figs.  18  and  19),  serving  as  a  case  for  the  handle,  is  of 
a  cylindrical  shape  externally,  while  the  other  and  in¬ 
ternal  one  is  conical ;  the  mill  revolving  in  a  vertical 
instead  of  a  horizontal  direction.  The  outer  cylinder, 


TAN,  OR  POWDERED  OAK  BARKS. 


125 


12,  is  fixed  by  an  iron  framework,  10,  to  the  wooden 
supports  of  the  mill,  while  the  inner  cylinder,  11,  is 
movable.  This  cylinder  and  the  inner  surface  of  the 
outer  one,  are  both  fluted  with  longitudinal  grooves,  de¬ 
scribing  curves  along  their  length.  Each  of  these  grooves 
is  divided  into  two,  at  the  larger  end  of  the  cylinder,  and 
into  four  at  the  smaller  end,  the  separation  commencing 
at  the  middle.  The  inner  cylinder  can  be  completely 
encased  in  the  outer  one,  by  the  turning  of  the  screws, 
14,  and  the  arrangement  of  grooves  is  intended  to  effect 
a  more  or  less  complete  division  of  the  particles  of  tan. 

When  the  cylinders  are  closely  in  contact,  the  bark  is 
first  exposed  to  the  action  of  the  larger  grooves,  which 
are  deeper  than  the  others,  and  then  becomes  engaged 
in  the  second  and  third  divisions,  by  means  of  which  it 
is  reduced  to  a  fine  powder.  If  it  be  desired  to  pro¬ 
duce  a  less  complete  trituration,  the  screws,  14,  are  loos¬ 
ened,  and  the  spring,  13,  then  presses  the  inner  cylinder 


Fig.  18. 


from  its  place,  in  such  a  manner  that  the  bark  is  only 
acted  upon  by  the  larger  grooves. 


126 


CHEMISTRY  OF  TANNING. 


t 


Fig.  18.  1. 
2. 

3. 

4, 
6. 

7. 

8, 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 
19. 


Hopper  of  the  mill. 

Spout  of  the  hopper. 

Regulator  of  the  spout. 

5.  Escapement  wheel. 

Handle  of  the  regulator. 
bis,  strap  attached  to  the  spout. 

9,  10.  The  spout  and  its  motive  appli¬ 
ances — spring  and  strap. 
Handle  for  turning  the  machine. 

Arm  of  the  lever  turning  the  spout. 
Trundle. 

Large  cog-wheel. 

Small  cog-wheel. 

Internal  conical  cylinder. 

External  conical  cylinder. 

Trough  for  receiving  the  tan. 

Wooden  framework. 


Fig.  19. 


C&L- 


n 


y 


& 


i'i 


u* 


Fig.  19.  1.  Fly-wheel. 

2.  Spout  under  the  hopper. 

3.  Hopper. 

4.  Trundle. 

5.  Lever  arm  for  turning  the  spout. 

6.  Axle  of  the  lever. 

7.  8,  9.  The  motor  and  regulating  appli¬ 

ances  of  the  spout. 

10.  Framework  supporting  the  cylinders. 


TAN,  OR  POWDERED  OAK  BARKS. 


127 


11.  Internal  cylinder,  with  grooves  cut  as 

before  described. 

12.  External  cylinder  channelled  like  the 

inner  one. 

13.  Spring,  regulating  the  inner  cylinder. 

11,  15.  Compressing  screws  acting  upon  this 

cylinder. 

16.  Spring  acting  upon  the  spout. 

17.  Escapement  wheel. 

18.  Regulator  of  the  spout. 

19.  Handle  of  the  regulator. 

20.  Axis  of  the  cylinders. 

21.  Small  canting-wheel. 

22.  Large  canting-wheel. 

23.  Axle  of  the  trundle  and  fly-wheel. 

24.  Crank. 

25.  Wooden  framework. 

Lespmasse’s  Bark  Mill. — This  apparatus  was  invented 
in  1843,  and  is  described  in  vol.  lix.  at  page  428,  of  the 
French  expired  patent  reports.  Fig.  20,  d,  iron  shaft 
turned  by  the  pinion,  moved  by  the  power,  and  support¬ 
ing  and  moving  the  stops  of  the  rammers  or  stampers, 
c,  shown  at  k  in  the  figure.  This  shaft  acts  upon  the 
conical  pinion  e,  and  through  it  upon  the  similar  verti¬ 
cal  pinion  f,  which  communicates  the  motion  to  a  small 
horizontal  shaft,  l,  upon  which  there  is  another  similar 
pinion,  <jr,  by  means  of  which  the  horizontal  pinion,  h, 
is  made  to  revolve.  This  latter  transmits  the  motion 
to  a  vertical  shaft,  o,  and  gives  a  reciprocating  move¬ 
ment  by  means  of  the  pinions,  e,  f,  g ,  A,  to  the  curb,  m, 
placed  horizontally  between  the  sides  of  the  rammer,  n. 
This  curb,  by  its  constant  movement  to  and  fro,  forces 
the  portions  of  bark  divided  by  the  knives  of  the  ram¬ 
mer,  n ,  through  the  holes,  x ,  made  of  different  dimen¬ 
sions  in  the  sides  of  the  apparatus,  into  the  conduit,  t, 
and  the  trough,  u.  Above  this  latter  is  a  drum  z,  con¬ 
nected  by  a  strap,  5,  to  which  the  buckets,  6,  are  adapted 
with  a  similar  drum,  z'.  These  two  drums  are  made  to 
revolve  by  a  strap  v,  moving  at  one  end  over  a  drum,  7, 


128 


CHEMISTRY  OF  TANNING. 


Fig.  20. 


placed  at  the  extremity  of  the  shaft,  d ,  and  at  the  other, 
upon  another  drum,  7',  above  the  preceding,  and  which 
is  connected  -with  that  supporting  the  strap,  5,  with  the 
buckets,  so  that  these  latter,  in  their  revolution,  become 
filled  with  the  tan  in  the  trough,  u ,  and  empty  it  into 
the  wooden  hopper,  8. 

In  the  bottom  of  this  hopper  is  an  opening  connected 
with  a  wooden  conduit,  leading  to  a  sieve,  which  is  di¬ 
vided  lengthwise  into  three  parts,  each  of  which  is  per¬ 
forated  with  holes  of  different  sizes.  This  sieve  is  moved 
by  an  arrangement  below  it,  which  is  connected  with  the 
strap,  y. 

12.  Troughs  to  receive  the  residue  from  the  sieve,  10. 

1 3.  Bags  in  which  the  residue  of  tan  is  placed. 


TAN,  OR  POWDERED  OAK  BARKS. 


129 


14.  Cords  keeping  the  bags  in  place  under  the  mouth 
of  the  trough. 

15.  Lever  of  the  rammers. 

i.  Arched  framework  for  keeping  the  shaft,  o,  in  a 
vertical  position.  This  shaft  is  divided  into  two  parts, 
connected  by  means  of  a  coupling,  s,  which  may  be  sepa¬ 
rated  at  will,  by  means  of  an  iron  tool,^',  attached  to  the 
framework  of  the  machine. 

1.  Small  stops  for  regulating  the  movement  of  the 
rammers. 

2.  Cushions  through  which  the  arms  of  the  curb  pass. 

3.  Framework  supporting  the  horizontal  shaft,  l. 

4.  Supports  of  the  drums,  over  which  the  buckets 
revolve. 

a.  Wooden  framework  of  the  machine. 

b.  Beam  supporting  the  pegs  for  keeping  the  rammers 
at  rest.  v 

c.  Hammers  with  knives  at  their  lower  ends. 

16.  Cross-bars  made  to  revolve  by  the  shaft,  o ,  so  as 
to  strike  against  the  wooden  box,  t ,  and  hasten  the  de¬ 
scent  of  the  tan  into  the  trough. 

Wiltse’s  Mill. — This  machine,  known  as  the  “  Catskill 
Mill,”  and  extensively  used  in  the  tanneries  of  the  Uni- 


Fig.  21. 


ted  States,  is  made  by  A.  and  B.  Wiltse,  intelligent  and 
'enterprising  machinists  of  Catskill,  Greene  Co.,  New 
9 


130 


CHEMISTRY  OF  TANNING. 


York.  It  is  constructed  upon  the  principle  of  the  shears, 
the  teeth  being  arranged  with  their  edges  at  an  angle,  and 
thrown  forward,  so  that  the  bark  may  be  driven  in  and 
ground  rapidly,  and  passed  through  without  interruption. 
Fig.  21  represents  the  machine,  which  may  be  driven  by 
water  or  steam  power,  and  so  arranged  as  to  receive  the 
bark  from  the  breaker  and  to  deliver  it  ground  in  the 
leach- vats.  .  To  give  a  better  idea  of  the  manner  in  which 
it  works,  we  give,  on  page  131,  a  plan  showing  the  rela¬ 
tive  positions  of  the  breaker,  bark-mill,  and  leach-vat. 
Fig.  2*2  is  drawn  upon  a  scale  of  a  quarter  of  an  inch  to 
one  foot. 

A  is  the  water-wheel,  and  C  its  shaft ;  B  is  the  bevel- 
wheel  which  drives  the  bevel  pinion  D  on  the  foot  of 
the  main  upright  I ,  which  also  carries  a  spur-wheel  E, 
and  drives  a  spur-pinion  F  on  the  shaft  G.  The  top  of 
the  mill  sets  ten  inches  below  the  second  floor,  in  order 
to  admit  the  bark  running  from  the  cracker  J,  AT, 
above.  This  latter  consists  of  a  cast-iron  curb  or  hoop 
J,  of  18  inches  diameter,  and  ten  inches  depth,  with 
three  jagged  teeth,  as  shown  in  end  and  interior  views 
at  j.  The  top  of  the  cracker  K  is  made  of  two  blocks 
of  wood,  firmly  secured  to  two  uprights,  represented  by 
the  dotted  lines,  by  means  of  bolts  passing  through  the 
portion  which  laps  them.  The  two  blocks  of  K  have 
openings  in  their  centres,  of  18  inches  diameter  at  the 
base,  and  24  inches  at  the  top,  to  correspond  with  the 
size  of  the  curb  on  which  they  rest.  About  Ih  inches 
from  the  bottom  are  four  strong  wrought-iron  teeth,  so 
inserted  as  to  be  in  the  centre  between  the  teeth  on  B,  r. 
The  latter  are  secured  to  the  shaft  I,  inside  of  K,  as  in¬ 
dicated  by  dotted  line ;  and  S,  s ,  is  also  similarly  placed 
on  shaft  L,  inside  of  J,j.  A  second  length  of  the  iron 
shaft  L,  drives  N  by  the  aid  of  the  bevel-wheels  M  and 
A7,  which  are  so  geared  as  to  drive,  in  turn,  the  pulley- 
shaft  O  at  the  head  of  the  elevators.  The  elevators  take 
the  bark  from  the  mill  and  deliver  it  into  a  bark-room 
or  loft  above  the  leach-tubs  Q,  whence  it  may  be  drawn, 
as  wanted,  through  a  trap. 

The  drawing  shows  two  leach-tubs,  but  the  number 


Fig.  22. 


TAN,  OR  POWDERED  OAK  BARKS.  131 


132 


CHEMISTRY  OF  TANNING. 


may  be  increased  according  to  the  demands  of  the  tan¬ 
nery. 

The  above  mill  possesses  superior  advantages,  as,  it 
does  its  work  effectually  and  with  despatch.  It  cuts  the 
fibre  of  the  bark  short,  without  flouring  it,  and  passes  it, 
even  when  wet,  without  becoming  clogged.  It  is  de¬ 
signed,  also,  for  purposes  of  economy  and  durability,  as 
well  as  of  convenience ;  the  arrangements  of  the  parts 
being  such,  that  when  any  of  them,  by  wear,  require  re¬ 
newal,  they  may  be  easily  removed  and  replaced  by 
others. 

When  worked  to  its  utmost  capacity,  it  will  grind 
from  one  to  two  cords  of  bark  per  hour,  and  must  be 
driven  at  the  rate  of  150  revolutions  per  minute  by  a 
ten-horse  engine.  At  100  revolutions  it  is  less  efficient. 
With  one  horse  power,  it  may  be  driven  at  the  rate  of 
five  revolutions  per  minute,  and  will  then  grind  one 
cord  in  from  one  to  three  hours.  The  cracker  should 
move  at  the  rate  of  30  to  40  revolutions  per  minute. 

If  steam  is  used  as  the  propelling  force,  the  waste 
steam  may  be  economized  and  applied  to  heating  the 


Fig.  23. 


leach-vats.  A  convenient  arrangement  for  this  purpose 
is  constructed  by  the  Messrs.  Wiltse. 

Birely’s  Mill — Another  ingenious  grinding  apparatus 


TAN,  OR  POWDERED  OAK  BARKS. 


133 


is  that  invented  by  Mr.  Valentine  Birely,  of  Frederick 
County,  Maryland.  It  reduces  the  bark  to  shreds  and 
strings,  forms  favorable  to  the  entire  extraction  of  its 
soluble  matter  by  the  liquor  of  the  vats.  Fig.  23  pre¬ 
sents  a  perspective  view,  and  Fig.  24  a  vertical  cross- 
section  of  the  machine. 

The  framework  is  of  cast-iron,  with  apertures  at  the 
sides  for  the  journals  of  three  cylinders,  and  flanges  and 
ribs  for  securing  a  wooden  hopper.  These  cylinders  are 


Fi<r.  24. 


of  different  diameters,  and  are  propelled  by  means  of  a 
drum  and  cogs  at  the  ends.  Being  denticulated  on  their 
surfaces,  and  revolving  in  concaves  similarly  studded 
with  teeth,  and  arranged  in  alternate  order  to  correspond 
with  the  reversed  movements  of  the  cylinders,  the  bark 


134 


CHEMISTRY  OF  TANNING. 


is  reduced  with  great  readiness,  and  the  mill  runs  with¬ 
out  obstruction.  The  coarse  teeth  of  the  first  cylinder 
break  it  down  preparatory  to  its  passage  through  the 
next,  and  finally  the  last  cylinder,  which  delivers  it 
ground  to  the  required  degree  of  fineness. 

These  mills  are  made  of  three  sizes,  and  the  largest, 
driven  by  a  ten-horse  power  engine  at  the  rate  of  80 
revolutions  per  minute,  will  turn  out  twenty-five  cords 
of  bark  every  twelve  hours. 

The  lengths  of  the  cylinders  in  the  three  different  sizes 
are,  respectively,  21,  24,  and  33  inches  ;  and  the  smaller 
ones  grind  in  proportion  to  the  power  applied. 

CHAPTER  XVI. 

TANNING  EXTRACTS. 

For  some  years  past,  tanners  have  endeavored  to  ac¬ 
celerate  the  tanning  process;  and  this  end  can  be  attained 
only  by  the  use  of  materials  very  rich  in  tannin,  and  in 
small  bulk.  That  is  the  reason  why  Catechu  or  terra 
japonica  is  so  extensively  used  now.  But  many  tanners, 
and  we  think  they  are  right,  object  to  the  use  of  this 
substance,  and  prefer  barks.  We  have  been  struck  for 
a  long  time  with  the  fact  that  no  one  has  yet  conceived 
the  idea  of  manufacturing  from  bark  an  article  having 
all  the  properties  of  oak  or  hemlock,  and  containing  as 
much  tannin  as  catechu.  Several  improvements  have 
been  made  lately  in  the  manufacture  of  extracts  proper 
for  accelerating  the  tanning  process,  but  those  improve¬ 
ments  are  not  yet  complete,  for  in  these  extracts  a  large 
portion  of  the  tannin  is  destroyed  and  transformed  into 
extractive.  Before  giving  the  process  for  manufacturing 
an  extract  containing  all  the  tannin  in  an  unaltered 
state,  we  shall  give  descriptions  of  the  processes  lately 
introduced. 

J.  ConneV s  Concentrated  Extract. — This  extract  is  thus 
prepared  :  He  makes  an  inspissated  extract  of  the  bark, 
that  is,  he  exhausts  it  completely  by  water,  then  evapo- 


TANNING  EXTRACTS. 


135 


rates  it  over  fire  in  syrupy  consistency,  and  dries  it  in 
connection  with  bark  dust. 

This  extract  has  two  inconveniences:  1st.  A  part  of 
the  tannin,  by  the  action  of  air  and  heat,  is  transformed 
into  extractive  matter  and  a  brown  coloring  matter  is 
developed.  2d.  This  extract  will  not  dissolve  entirely 
in  water. 

Its  only  advantage  is  in  being  a  little  richer  in  t&nnin 
than  the  bark  employed. 

A.  Steer's  Process. — We  are  unacquainted  with  the 
mode  of  preparation  of  this  extract ;  but  from  what  we 
have  seen  we  believe  that  the  process  is  the  same  as  the 
above. 

According  to  Mr.  Steers  the  process  for  reducing  the 
tanning  properties  of  the  bark  to  an  extract  only  of 
the  original  bulk  of  the  crude  bark  offers  the  following 
advantages : — 

The  means  of  controlling  the  purchases  of  hides  and 
sales  of  leather  by  enabling  tanners  to  choose  suitable 
city  locations  for  their  tanning  operations,  as  the  induce¬ 
ments  of  supply  and  demand  may  determine. 

The  means  of  securing  a  certain  and  permanent  sup¬ 
ply  of  tanning  material  at  a  uniform  and  unvarying 
figure  to  conduct  their  operations,  and  that  figure  less 
than  the  amount  now  paid  by  the  most  remote  bush 
tanners. 

To  bush  tanners  the  means  of  obtaining  25  per  cent, 
more  tanning  material  out  of  the  same  quantity  of  bark 
without  increasing  the  cost  of  extraction. 

To  both  city  and  country  tanners  the  facilities  of  mak¬ 
ing  liquors  of  any  and  every  desirable  amount  of  strength, 
to  the  want  of  which  is  generally  attributed  the  tanner’s 
greatest  difficulty  in  attempting  to  compete  with  the 
European  tanners  in  sole-leather. 

To  curers  of  bark  and  manufacturers  of  bark  extracts 
for  tanners’  purposes,  besides  the  basis  of  the  proposed 
trade  being  of  the  most  stable  character,  and  giving  to 
those  who  engage  in  it  an  unusual  control  over  the 
subduing  and  settlement  of  wild  lands,  it  secures  to  their 
operation  in  extract  an  immense  direct  profit,  clearly  ex- 


136 


CHEMISTRY  OF  TANNING. 


hibited  and  fairly  calculated  by  assuming  the  difference 
of  price  between  the  place  bark  is  procured  at,  and  the 
place  it  is  consumed  as  profits. 

By  this  process  of  tanning  butts  and  middlings,  the 
hides  being  prepared  in  the  usual  manner  and  tanned 
with  ordinary  liquors,  the  most  perfect  tanning  of  the 
heaviest  sole-leather  is  effected  within  four  days,  and  an 
unusually  great  gain  of  weight  is  obtained,  with  a  con¬ 
sequent  rendering  of  the  leather  almost  impervious  to 
water,  together  with  a  susceptibility  of  a  very  improved 
finish.  There  is  also  a  vast  saving  of  tannic  acid,  as  the 
unavoidable  loss  by  volatility  in  the  common  exposure 
of  present  tanneries  is  equal  to  50  per  cent,  of  the  bark 
used  therein,  as  shown  by  the  experiments  of  chemists 
and  the  statistics  of  large  American  tanneries. 

As  we  have  said  above,  the  author  of  this  book  has 
had  occasion  to  examine  this  extract,  and  it  contains  a 
large  quantity  of  extractive  matter,  a  sure  sign  of  destruc¬ 
tion  of  tannin.  He  tried  it  on  a  calf-skin,  and  it  re¬ 
quired  two  weeks  to  be  completely  transformed  into 
leather. 

It  is  true  that  the  above  advantages  are  exaggerated, 
but,  nevertheless,  the  introduction  of  this  extract  is  an 
improvement.  We  shall  now  describe  a  process  we  have 
tried,  and  which  has  succeeded  with  us  very  well. 

We  use  the  following  apparatus: — 

Fig.  25. 


AAA,  ordinary  wooden  barrels  of  a  capacity  of  40  gal¬ 
lons.  The  bottom  of  each  barrel  is  covered  with  straw. 


TANNING  EXTRACTS. 


137 


Each  is  filled  with  the  bark  we  mean  to  treat,  which  is 
covered  with  20  gallons  of  water.  Leave  24  hours,  and 
then  introduce  the  steam  by  the  main  pipe  CC.  Leave 
it  to  disengage  until  the  barrel  is  full,  then  shut  the 
cocks  BBB  and  leave  12  hours.  Draw  the  liquor  by  the 
pipes  DDD.  All  the  liquid  is  introduced  into  a  vacuum 
pan  and  distilled  at  a  temperature  which  does  not  exceed 
120°.  Continue  to  exhaust  the  bark  as  above  described, 
till  the  water  is  nearly  colorless,  and  evaporate  all  the 
liquors  in  the  vacuum  pan. 

When  the  evaporation  is  completed,  the  extract  is 
drawn  off  in  a  jar  and  left  to  cool. 

It  is  easy  to  ascertain  when  the  evaporation  is  achieved; 
for  that  purpose  take  out  a  little  of  the  extract  and  let 
it  cool ;  on  cooling  it  will  become  hard  enough  to  be 
broken  with  the  fingers. 

Such  extract  has  all  the  properties  of  the  bark  reduced 
to  a  small  volume,  and  the  evaporation  being  made  at  a 
low  temperature  without  the  contact  of  the  air,  the 
tannin  is  unaltered. 


1  lb.  Extract 

of  White-oak  bark  represents  . 

6  lbs.  of  bark. 

J  it  It 

“  Avens  root  “ 

ll 

4  <<  << 

J  It  ll 

“  Sumach  “ 

it 

6  “ 

^  ll  ll 

“  Divi-divi  “ 

It 

4  “  “ 

J  ((  It 

“  Valonia  11 

ll 

4  “  « 

J  ll  ll 

“  Hemlock  “ 

ll 

4  “  “ 

The  above  table  shows  that 

these  extracts  are  richer 

in  tannin  than  catechu,  and  have  at  the  same  time  all 
the  properties  of  the  bark  employed.  We  hope  to  see 
them  used  in  preference  to  any  other.  The  editor  of 
this  work  has  made  many  experiments  on  this  subject, 
but  unhappily  they  are  not  achieved  and  are  uncom¬ 
pleted,  but,  when  terminated,  he  will  publish  them,  as 
they  will  be  of  great  interest  to  practical  tanners. 


138 


CHEMISTRY  OF  TANNING. 


SECTION  III. 

SKIN. 

CHAPTER  XVII. 

PROXIMATE  PRINCIPLES  OF  LEATHER— STRUCTURE 
OF  THE  SKIN. 

Proximate  Principles  of  Leather. — As  may  be  inferred 
from  its  nature,  leather  is  formed  by  the  combination 
of  the  substance  of  the  skin  with  any  other  compound 
which  has  the  property  of  rendering  it  imputrescible 
and  elastic.  Many  substances  possessing  these  proper¬ 
ties  in  relation  to  skins  of  animals,  are  known  to  exist 
both  in  the  organic  and  inorganic  classes ;  but  the  one 
most  generally  employed  as  well  as  the  most  efficient  is 
tannin.  That  a  firm  chemical  union  of  the  two  bodies, 
such  as  that  above  referred  to,  exists,  is  evidenced  by 
the  modified  form  of  the  material,  and  the  physical  ap¬ 
pearance  and  chemical  behavior  of  leather,  when  sub¬ 
jected  to  microscopical  and  chemical  examinations.  The 
principle  in  the  skin  esteemed  by  the  tanner  is  a  gelatino- 
fibrous  compound,  which  constitutes  the  basis  of  leather ; 
and  the  combining  agent — tannin — partakes  of  an  acid 
nature,  so  that  by  uniting  with  the  gelatino-fibrous 
material,  the  former  is,  as  it  were,  thereby  salified,  so 
that  it  is  no  longer  subject  to  the  ready  putrefactive 
change  which  the  skin  undergoes  under  the  influence  of 
air  and  moisture.  As  the  gelatino-fibrous  principle  forms 
only  one  of  several  others  in  the  hide  of  the  animal,  so 
the  tannin  constitutes  only  one  among  many  other  sub¬ 
stances  in  the  sources  whence  it  is  extracted. 

Structure  of  the  Skin. — Strictly  speaking,  the  skin  of 
animals  is  composed  of  two  parts,  the  corium  or  cutis, 
and  the  cuticle  or  epidermis  ;  the  former  is  the  portion 
which  enters  into  the  composition  of  leather,  and  forms 
the  true  skin ;  and  the  latter  constitutes  the  exterior 
covering  in  which  the  fur,  wool,  or  hair  of  the  animal 


SKIN. 


139 


is  rooted.  Some  physiologists,  however,  distinguish 
three  distinct  parts  in  the  skin,  namely,  the  corium,  rete 
mucosum,  and  the  cuticle.  These  several  parts  are  illus¬ 
trated  in  the  two  following  figures. 

Fig.  27. 


C 


The  former,  Fig.  26,  shows  the  position  of  the  hair, 
and  the  latter,  Fig.  27,  the  magnified  layers  of  which  the 
skin  is  composed.  In  both  A  represents  the  epidermis ; 
B  the  rete  mucosum  in  which  the  roots  of  the  hair  are 
imbedded ;  C  the  fibrous  tissue  of  the  true  skin  ;  and  D 
the  cellular  tissue  beneath  the  latter,  showing  the  fat 
cells,  a,  in  the  latter  figure,  and  sweat  glands,  b ,  with 
the  follicles,  h,  through  which  this  secretion  passes  out 
to  the  surface  of  the  skin. 

Behavior  of  the  Epidermis  and  Cutis  with  Reagents. — 
When  the  fresh  skin  is  immersed  and  macerated  re¬ 
peatedly  in  water,  the  matter  of  the  cuticle  is  separated 
from  the  fibrous  substance  of  the  cutis,  not  by  the  solu¬ 
tion  of  the  former,  but,  as  it  would  appear,  by  dissolving 
an  extractive  matter  amounting,  according  to  Weinliolfs 
analysis,  to  about  8£  per  cent.,  and  which  is  probably, 


140 


CHEMISTRY  OF  TANNING. 


to  some  extent,  intermediate  between  the  horny  matter 
of  the  cuticle  and  the  cutis.  Weak  acids  also  abstract 
it,  but  solutions  of  the  alkalies  and  of  many  of  their 
salts  are  more  effectual  for  bringing  about  the  separa¬ 
tion,  since  these  agents  dissolve  it.  The  epidermis, 
which  is  analogous  to  horn,  does  not  combine  with  tan¬ 
nin  or  any  other  substance,  by  the  agency  of  which 
leather  is  produced.  Hence  it  becomes  useless  to  the 
tanner,  and  therefore  the  first  process  to  which  hides 
and  skins  are  subjected  by  him  is  that  for  removing 
the  hair  and  epidermis,  both  being  useless. 

The  corium,  deprived  of  the  epidermis,  is  a  substance 
formed  of  a  number  of  fibres  ramifying  and  intersecting 
one  another  in  every  position,  leaving,  however,  inter¬ 
stices  contracting  in  size  as  they  reach  the  other  portion, 
and  which  are  more  or  less  charged  with  fluid  matter, 
that  serves  to  renew  the  cuticle,  and  keep  the  skin  pliant 
and  moist.  On  treating  the  skin  with  water  these  mat¬ 
ters  are  removed,  and  ultimately  there  remains  but  the 
fibrous  portion  saturated  with  water.  In  this  state  it 
appears  semi-transparent,  and  if  the  water  be  expelled 
by  a  gentle  heat,  it  assumes  the  physical  appearance  of 
horn,  constituting  only  about  32^  to  33  per  cent,  of  the 
raw  hide. 

From  Weinholt’s  researches,  it  appears  that  the  skin 
deprived  of  the  epidermis  and  its  subjacent  fluid,  as  also 
of  the  mucous  membrane  and  fat  on  the  interior,  affords 
43  per  cent,  of  solid  matter,  yielding: — 


Fibrous  matter  ......  14.42 

Uncoagulated  albumen  .....  3.49 

Extractive  matter  insoluble  in  alcohol  .  .  11.44 

“  “  soluble  “  .  .  2.32 

Fatty  matter  and  loss  .  .  .  .  .2.33 


100.00 

Digestion  in  water  removes  the  albumen  and  extrac¬ 
tive  matter  taken  up  by  this  menstruum  ;  in  alcohol  the 
further  portion  of  extract  dissolves,  and  ether  separates 
the  fat  with  which  the  residue  is  impregnated.  If  the 
corium,  deprived  of  the  epidermis  is  treated  with  boil- 


CONSTITUTION  OF  THE  SKIN. 


141 


ing  water,  it  dissolves  with  the  exception  of  a  little  fat 
and  some  nervous  filaments ;  and  when  the  liquid  is 
evaporated  slowly,  a  gelatinous  residue  is  left,  which 
when  the  entire  skin  is  operated  upon  forms  the  glue  of 
commerce. 

This  effect  of  the  water  does  not  arise,  however,  from 
the  solution  of  the  gelatine  which,  as  might  be  supposed, 
the  skin  contains;  but  it  modifies  the  components  of  the 
fibrous  tissue,  so  as  to  bring  them  into  this  compound. 
The  same  property  is  possessed  by  acids  and  by  alkalies 
in  a  more  powerful  degree,  since  the  change  is  effected 
by  these  agents  at  the  ordinary  temperature. 

CHAPTER  XVIII. 

CONSTITUTION  OF  THE  SKIN. 

FIBKIN — GELATINE — ALBUMEN. 

Composition  of  the  Skin. 

Haying  treated  of  the  structure  of  the  skin,  we  pro¬ 
ceed  naturally  to  consider  its  composition.  The  skin  of 
animals  consists  of  fibrin,  gelatine,  and  small  portions  of 
albumen  and  fatty  matter.  The  first  two  form,  as  it 
were,  the  basis  or  network  of  the  whole  tissue,  a  portion 
of  which,  if  boiled  with  water,  yields  its  gelatine  while 
the  fibrin  remains.  The  epidermis  of  the  skin  does  not 
combine  with  tannin.  The  properties  of  these  sub¬ 
stances  which  play  such  an  important  part  in  tanning 
are  as  follows  : — - 

Fibrin — Exists  in  the  animal  structure  as  the  basis  of 
the  muscular  tissue.  It  occurs  in  solution  in  lymph, 
chyle,  and  blood,  from  which  it  separates  by  coagulation, 
as  soon  as  these  fluids  cease  to  form  a  part  of  the  living 
organisms.  It  is  prepared  by  carefully  whipping  blood ; 
it  separates  in  elastic,  stringy  masses,  which  must  be 
washed  repeatedly  with  water  to  remove  coloring  mat¬ 
ter,  and  digested  frequently  with  alcohol  and  ether  to 
free  it  from  fatty  substances.  Dry  fibrin  is  an  opaque, 
yellowish  mass ;  if  transparent,  it  indicates  the  pre- 


142 


CHEMISTRY  OF  TANNING. 


sence  of  some  fat.  Insoluble  in  alcohol  and  ether. 
Digested  for  a  long  time  in  water  at  390°  it  is  dissolved 
with  a  slight  decomposition  ;  it  is  thrown  down  from  its 
solution  by  acids.  Its  solubility  in  saline  solutions  has 
been  tested  ;  when  saturated  it  forms  clear  viscid  liquids 
generally  coagulable  by  boiling.  When  burned  it  gives 
the  same  smell  as  albumen  and  yields  ashes  composed  of 
phosphate  of  lime  and  magnesia. 

In  sulphuric  and  mono  or  bibasic  phosphoric  acid  it 
becomes  gelatinous,  and  forms  a  neutral  compound  solu¬ 
ble  in  water.  Nitric  acid  converts  it  into  xanthoproteic 
acid.  When  dry  it  forms  a  blue  solution  in  strong  hy¬ 
drochloric  acid. 

Muscular  and  venous  fibrin  both  dissolve  at  a  gentle 
heat,  in  acetate  of  soda,  hydrochlorate  of  ammonia  and 
nitrate  of  potash,  forming  solutions  coagulable  by  heat, 
and  exhibiting  the  properties  of  dissolved  albumen  ;  but 
neither  arterial  fibrin  nor  that  of  the  buffy  coat  can 
undergo  this  change.  By  putrefaction  it  is  transformed 
into  a  volatile  fatty  body  having  the  characteristics  of 
butyric  acid.  The  same  result  is  produced  by  heating 
it  with  potash  lime  at  320°  to  356°. 

Its  ultimate  percentage  composition,  according  to 
Messrs.  Dumas  and  Cahours,  is — 

Carbon  52.78 
Hydrogen  6.96 

Oxygen  23.48  (with  some  sulphur  and  phosphorus) 
Nitrogen  16.78 


100.00 

Its  formula  is  C40H31O1oNS-JPh,  or  lOPR+SPh. 

Pure  fibrin,  when  added  to  water  acidulated  with  hy¬ 
drochloric  acid  and  containing  yeast,  forms  a  clear  solu¬ 
tion  similar  to  that  of  protein,  and  from  which  acid  and 
alum  precipitate  a  flocculent  body.  Without  yeast  a 
temperature  of  212°  will  produce  the  same  effect.  By 
evaporation  in  vacuo  it  leaves  a  light  yellow  residue 
analogous  to  dry  white  of  egg,  soluble  in  warm  water, 
but  not  coagulable  by  heat.  After  separating  the  dis¬ 
solved  part  from  the  acid  it  has  a  composition  closely 


CONSTITUTION  OF  THE  SKIN. 


143 


approximating  to  chondrin ,  but  without  its  chemical 
properties. 

Gelatine — Is  a  solid,  transparent,  colorless,  corneus 
substance,  which  forms  with  boiling  water  a  solution 
that,  on  cooling,  takes  the  consistency  of  a  jelly.  In 
its  natural  state  and  as  existing  in  the  cellular  tissue, 
bones,  tendons,  etc.,  to  which  in  their  woof  it  serves 
to  give  form,  it  has  the  name  of  histose.  This  latter 
being  treated  with  boiling  water  and  dried,  becomes 
gelatine ;  but,  previous  to  this  action,  bears  the  same 
relation  to  the  latter,  in  appearance  and  properties,  as 
can  exist  between  a  completely  organized  body  and  its 
constituent  elements  in  a  state  of  complete  desiccation. 

Chondrin  is  the  gelatine  of  cartilages,  and  is  precipi¬ 
tated  by  acids,  alum,  and  salts  of  lead.  Glue  is  the 
technical  term  for  the  gelatine  of  bones,  hoofs,  and 
hides,  isinglass  for  that  from  certain  fishes,  and  size  for 
the  aqueous  extract  of  parchment  scraps  and  several  ani¬ 
mal  membranes.  At  212°  gelatine  softens  and  melts, 
but  at  a  higher  temperature  it  decomposes  into  animal 
products  and  a  slight  residue  of  earthy  matters.  In  cold 
water  it  swells  up  and  loses  its  solidity,  but  when  impreg¬ 
nated  with  water,  if  heated  at  140°,  it  becomes  so  mi¬ 
nutely  suspended  as  to  give  to  the  liquid  the  appearance 
of  a  solution  insoluble  in  alcohol  and  ether.  With 
tannin  it  forms  a  very  intimate  combination,  and  Muller 
considers  this  compound  as  definitely  proportioned. 
Gelatine  is  transformed  by  nitric  acid  into  oxalic  acid ; 
sulphuric  acid  transforms  it  into  sugar  of  gelatine ,  or 
glycocol,  leucin ,  and  sulphate  of  ammonia. 

Potash  converts  it  into  a  mixture  of  sugar  of  gelatine 
and  leucin,  and  though  not  of  the  protein  series,  it  may, 
nevertheless,  contribute  to  the  nutrition  of  the  gelatinous 
tissues.  Bichloride  of  mercury  coagulates  and  renders 
it  insoluble,  but  an  excess  of  gelatine  dissolves  the  mer¬ 
curial  compound. 

By  long  digestion  at  212°  gelatine  loses  its  gelatinizing 
power,  and  forms,  on  evaporation,  a  gummy  mass,  readily 
soluble  in  cold  water. 


144 


CHEMISTRY  OF  TANNING. 


The  ultimate  composition  of  gelatine  is: — 


Lowig. 

Muller. 

Carbon 

50.00 

50  04 

Hydrogen 

6.41 

6.46 

Oxygen 

25.64' 

25.13 

Nitrogen 

17.95 

18.36 

100.00 

100.00 

Its  formula  is  C13H10O5N2. 

Albumen. — Albumen  is  a  component  of  nearly  all  the 
animal  solids;  and  when  free  from  foreign  matters  is 
soluble  in  water.  This  solution  coagulates  at  160°,  but 
the  coagulum  may  be  redissolved,  by  heating  it  with 
water  in  a  digester  at  400°. 

As  precipitated  from  the  aqueous  solution  of  white 
of  eggs,  or  of  the  serum  of  blood,  it  is  pure  and  soluble 
in  acetic  acid,  very  weak  alkalies,  and  in  soluble  alka¬ 
line  salts. 

Albuminous  solutions  are  precipitated  by  sulphuric 
acid;  hydrochloric  acid  produces  a  coagulum  soluble  in 
water,  and  in  strong  hydrochloric  acid  by  heat.  Nitric 
acid  throws  down  a  iiocculent  precipitate,  soluble  in 
alkalies  even  from  very  dilute  solutions.  Acetic  acid 
gives  no  precipitate  even  by  heat,  unless  both  acid  and 
solution  are  concentrated.  In  that  case,  a  gelatinous 
compound,  soluble  in  both  acid  and  in  water,  is  formed ; 
albumen  is  soluble  in  alkalies;  water  of  lime,  baryta  and 
strontia  have  no  reaction  upon  the  aqueous  solution  of 
albumen,  but  with  the  alkaline  earths  themselves,  it 
forms  insoluble  compounds.  Earthy  and  metallic  salts 
throw  down  double  compounds,  one  with  acid  and  an¬ 
other  with  metallic  oxide,  the  latter  of  which  is  wholly 
insoluble,  while  the  former  is  not  entirely  so. 

Tannin  precipitates  albuminous  solutions,  but  the 
resulting  compound  is  not  softened  by  heat  like  the 
tanno-gelatine. 


PROPER  TREATMENT  OF  HIDES  AND  SKINS. 


145 


Pure  albumen  is  thus  formed: — 


Carbon  .  .  .  .  .  .  .  .  54.  Si 

Hydrogen  .  .  .  .  .  .  .  .7.09 

Nitrogen  ........  15. S3 

Oxygen  .  .  .  .  .  .  .  .31.23 

Phosphorus.  .......  0.33 

Sulphur  ........  0.63 


CHAPTER  XIX. 

THE  PROPER  TREATMENT  OF  HIDES  AND  SKINS— KTNDS 
OF  SKINS  SUITABLE  FOR  TANNING— SALTING  OF  THE 
HIDES. 

Proper  Treatment  of  Hides  and  Skins. 

Mr.  H.  F.  Lange,  Cordovan  leather  tanner,  in  the  late 
session  of  the  Oschatz  Trade  Association,  expressed  his 
regrets  that  in  the  process  of  fabrication,  that  is  to  say, 
in  the  preparation  of  the  hide  for  trade  purposes,  raw 
hides  and  skins  labored  under  great  disadvantages  owing 
to  the  farmers’  and  butchers’  handling,  inasmuch  as  this 
was  not  carefully  enough  done  with  a  view  to  the  future 
operations  to  be  undergone  by  the  raw  material.  This 
subject  of  complaint  was  also  concurred  in  by  the  bark 
and  white  tanners  present  at  the  meeting,  who  gave  ex 
pression  to  the  united  wish  that  through  the  making 
known  of  the  manipulations  which  experience  has 
proved  to  be  the  most  simple,  and,  at  the  same  time,  the 
most  efficacious,  hides  or  skins  may  be  delivered  in  a 
condition  perfectly  suitable  to  the  process  of  manufac¬ 
ture,  and  the  evils  more  closely  particularized  below 
might  gradually  be  done  away  with  as  much  as  possible. 

It  happens  only  too  often  that  the  hides  and  skins  of 
slaughtered  animals,  or  of  those  that  have  died  from 
natural  causes,  are  not  at  once  taken  off,  but  left  for 
days  together  on  the  carcass.  This  is  in  the  highest 
degree  detrimental  to  the  hides,  as  they  acquire  thin 
and  defective  spots,  through  the  process  of  decomposi¬ 
tion  going  on  in  the  carcass,  or  the  worms  which  are 
forming  in  the  interior  of  the  animal  work  destructively 
10 


146 


CHEMISTRY  OF  TANNING. 


upon  the  hides.  Great  damage  is  also  caused,  although 
of  not  so  great  a  nature,  if,  in  flaying,  the  work  is  not 
done  with  all  due  care.  The  bits  of  flesh  and  fat,  which 
are  only  too  often  allowed  to  remain  adhering  to  hides  and 
skins,  become  at  once  decayed  and  communicate  decay  to 
the  skin;  which  is  injured  or  eaten  away  in  spots,  be¬ 
coming,  consequently  and  subsequently,  very  thin  or  even 
worn  into  holes.  Such  damage  is  noticeable  in  a  more 
especial  manner  after  manufacture,  when  the  leather  is 
found  bad  in  appearance,  or  inoculated  with  dark  spots, 
as  is  the  case  with  colored  leather. 

And  leaving  these  defects  out  of  the  question,  the 
suppleness  and  durability  of  the  leather  itself  will  be  in¬ 
juriously  affected  if  the  skins  are  not  suitably  and  care¬ 
fully  treated  in  drying  and  hanging  up,  by  the  premature 
shrinking  and  imperfect  drying  of  the  material. 

As  an  evidence  that  the  evils  just  mentioned,  arising 
from  improper  treatment,  are  of  more  importance  than 
is  generally  thought,  we  give  the  statement  of  Mr. 
Lange  to  the  effect  that  the  sheepskins  received  in  the 
summer  season  often  yield  barely  one-third  of  a  material 
perfectly  adapted  to  the  fabrication  of  imitation  mo¬ 
rocco  leather. 

In  view  of  these  evils,  and  in  order  to  promote  the 
interests  of  the  leather  trade,  the  following  points  are 
to  be  urgently  recommended  to  the  producers  of  the 
raw  material  in  flaying  hides  and  skins: — 

1st.  Immediately  after  the  death  of  the  animal  the 
hide  or  skin  should  be  carefully  taken  off. 

2d.  The  fleshy  or  fatty  portions  still  adhering  to  the 
skin  should  be  detached  down  to  the  smallest  pieces. 

3d.  The  hide  should,  without  the  least  delay,  be 
hung  up  in  a  very  airy  place,  one  not  exposed  to  damp¬ 
ness,  with  the  hair  side  inward,  so  that  a  draught  of  air 
may  play  upon  the  entire  length  of  the  inward  side  of 
the  hide. 

4th.  In  order  to  prevent  the  hide  from  shrinking,  the 
head  and  tail  ends  should  be  stretched  out,  and  nailed 
to  the  pole. 


PROPER  TREATMENT  OF  HIDES  AND  SKINS.  147 


5th.  The  hoofs  and  legs  should  be  spread  with  skewers 
on  both  sides. 

6th.  The  flaying  of  the  hide  should  not  be  intrusted 
to  inexperienced  persons;  for,  unless  a  certain  dexterity 
is  brought  into  this  operation,  the  value  of  the  skin  will 
be  considerably  lessened. 

Only  by  observing  these  directions  can  skins  and  hides 
be  properly  dried,  and  delivered  free  from  defects,  suit¬ 
able  for  valuable  use. 

The  benefits  that  will  accrue  to  the  whole  leather  trade 
by  following  such  a  course,  cannot  be  rated  too  highly ; 
for  not  only  will  it  secure  a  serviceable  material  to  man¬ 
ufacturers,  but  also  a  large  quantity  of  hides  and  skins 
will  be  saved  from  destruction,  and  the  market  will  be 
better  and  more  fully  supplied.  A  further  consequence 
will  also  be  that  a  better  manufactured  article  will  be 
produced,  and  lower  prices  established. 

Kinds  of  Skins  suitable  for  Tanning. 

The  principal  object  of  attention  in  the  preparation 
of  leather  is  the  hides  or  skins  of  the  animals.  Three 
classes  are  specified  in  commerce :  the  term  hide  is  ap¬ 
plied  to  the  skin  of  the  larger  and  full. grown  beasts; 
kip  to  the  skin  of  the  younger  animals  of  the  same  class; 
and  skin  indicates  the  hides  of  the  sheep,  goat,  kid,  and 
the  like.  The  term  kip  is  qualified  by  the  size  of  the 
skins.  Generally  speaking,  the  skins  which  are  con¬ 
verted  into  leather  are  those  of  oxen,  cows,  and  calves, 
of  the  sheep,  the  goat,  and  their  young,  of  the  horse, 
the  pig,  the  dog,  and  a  few  others ;  but  by  far  the  most 
extensively  worked,  as  well  as  the  more  important,  are 
ox,  cow,  and  horse-hides,  kips,  calf,  and  seal-skins. 
Considerable  difference  is  observed  in  the  thickness  and 
quality  of  the  skins  of  various  animals,  even  of  those  of 
the  same  class,  owing  to  circumstances  connected  with 
the  food,  age,  variety  of  breed,  the  state  of  health,  and 
even  the  period  of  the  year  when  they  are  slaughtered. 
Thus,  large  oxen  are  well  known  to  afford  hides  which 
are  tanned  into  thicker  and  heavier  leather  than  bulls 
or  cows,  especially  if  the  latter  be  old  and  have  had 


148 


CHEMISTRY  OF  TANNING. 


several  calves.  Bull-hides  are  coarser-grained,  and 
thinner  in  the  hack  than  those  of  oxen  and  heifers,  or 
young  cows,  but  much  denser  in  the  neck  and  parts  of 
the  belly.  It  would  also  appear  that  when  cows  have 
repeatedly  calved,  the  skin  becomes  distended  and 
thinner,  and  does  not,  therefore,  afford  as  heavy  a  sole- 
leather  as  that  of  younger  animals.  Again,  hides  of 
animals,  dying  in  a  state  of  disease,  are  found  to  be 
much  inferior  to  those  of  healthy  ones  of  the  same  class, 
although  the  apparent  difference  is  not  very  marked  be¬ 
fore  tanning. 

No  very  definite  criteria  are  known  to  guide  the  pur¬ 
chaser  in  distinguishing  the  quality  of  hides  and  skins. 
If  the  hide  be  thin,  flabby,  soft,  and  will  not  bear  han¬ 
dling,  then  such  a  one  will  not  make  good  leather ;  but 
should  it  present  the  opposite  quality,  it  may  confidently 
be  expected  to  be  a  good  article.  It  has  been  remarked 
of  sheep,  that  the  finer  wool  variety  have  inferior  skins ; 
also  that  the  skin  gains  in  thickness  and  quality  consi¬ 
derably  in  the  course  of  a  few  days  after  shearing. 

Ox-hides. — Under  this  head  may  be  enumerated  the 
skins  of  oxen ,  cows,  buffaloes,  and  calves.  In  Great  Britain 
and  Ireland,  the  market  draws  generally  upon  the  home 
produce,  but  the  largest  quantity  used  comes  from  South 
America,  the  East  and  West  Indies,  etc.  The  animals 
which  roam  along  the  Pampas  and  Llanos,  or  great 
plains,  in  herds  of  vast  numbers,  are,  in  addition  to 
those  owned  by  the  extensive  cattle  owners  or  hateros, 
the  stock  whence  the  vast  quantity  of  hides  used  is  an¬ 
nually  derived.  They  are  imported  in  the  dry  state, 
and  salted,  and  produce  a  very  good  sole-leather.  It 
should  be  remarked,  however,  that  the  hides  from  ani¬ 
mals  inhabiting  the  tropical  latitudes  are  not  so  well 
suited  for  tanning  as  those  from  the  temperate  and 
northern  parts  of  the  globe.  The  green  or  fresh  hides 
of  the  home  market  always  rate  higher  than  other  sorts, 
owing,  perhaps,  to  the  fact  that  they  do  not  require  so 
much  labor  as  the  imported  dry  kinds ;  still,  in  conse¬ 
quence  of  the  amount  of  water  they  contain  they  prove 
to  be  much  dearer  than  the  others ;  for,  allowing  that 


PROPER  TREATMENT  OF  HIDES  AND  SKINS.  149 


for  the  production  of  100  pounds  of  leather,  75  pounds 
of  dry  hide  are  requisite,  the  equivalent  of  this  of  salted 
hides  would  average  150  pounds,  and  185  of  green  or 
market  hides.  Heavy  hides  are  converted  into  sole,  belt, 
and  harness  leather,  also  for  carriage  coverings,  and  the 
smaller  and  lighter  kinds  aie  made  into  leather  much 
used  for  skirtings ,  and  for  enamelling.  That  which  is 
used  for  ladies’  shoes  and  for  bridle  leather  undergoes  a 
bleaching  process  termed  fair  finished.  Hides  from  the 
west  coast  of  Africa  make  good  upper  leather,  but  are 
much  employed  in  their  raw  state  for  trunk  covering. 

Calves’  skins  and  kips  of  home  produce  are  of  very 
superior  quality,  and  produce  a  leather,  when  made  with 
good  oak  bark,  very  extensively  worked  into  uppers  of 
shoes  and  boot  fronts.  In  France,  where  the  calf-skin 
leather  has  been  reputed  for  its  excellence,  they  are 
taken  off  the  animal  when  five  or  six  months  old.  Kips 
are  imported  from  the  East  Indies,  Buenos  Ayres,  and 
Montevideo ;  those  from  the  former  places  are  dried  and 
salted  or  merely  exsiccated ;  and  from  the  latter  places 
they  come  simply  salted.  The  lesser  and  inferior  kinds 
of  kids  and  calf-skins  are  tanned  for  bookbinders’  use, 
for  gloves,  and  the  manufacture  of  ladies’  boots  and  shoes. 

Buffaloes’  hides  are  tanned  like  ox-hides,  but  they 
make  an  inferior  quality  of  sole-leather.  When  tanned 
in  a  particular  way  with  oil,  they  constitute  what  is 
termed  huf-helt  leather ,  which  is  superior  to  the  similar 
article  made  of  cow-hides. 

Horse-hides. — The  skins  of  these  animals  are  much 
inferior  to  those  of  oxen  in  thickness,  texture,  and 
strength,  and  consequently  they  are  never  prepared  with 
the  view  of  making  sole-leather ,  though  the  better  quality 
is  used  when  tanned  for  uppers.  The  chief  consumption 
is,  however,  as  cordovan  or  enamelled  leather,  the  hides 
being  split  by  machinery  to  reduce  them  to  the  adapted 
thinness.  Horse-hides  are  likewise  made  into  tawed, 
white,  or  alum  leather,  and  are  in  this  state  used  as  aprons 
for  certain  classes  of  mechanics,  and  as  thongs  for  the 
manufacture  of  common  kinds  of  whips,  and  for  sewing 
common  harness. 


150 


CHEMISTRY  OF  TANNING. 


A  considerable  number  of  horse-hides  is  annually 
imported  from  South  America.  The  imported  hides  are 
much  superior  to  those  which  find  their  way  to  the  home 
market,  on  account  of  the  latter  belonging  generally  to 
old  and  worn-out  animals,  while  the  former  have  been 
flayed  from  the  captured  wild  horses  of  the  pampas, 
lying  between  the  chains  of  the  Andes.  Ass  and  mule’s 
hides,  tanned  and  so  prepared,  serve  for  the  manufacture 
of  scabbards ;  the  leather  is  called  shagreen  or  shagri. 

Sheep-skins. — The  home  supply  is  very  extensive,  and 
although  they  are  capable  of  making  only  a  spongy, 
weak  leather,  the  uses  to  which  they  are  devoted  are 
various,  and  their  manufacture  gives  employment  to 
numerous  hands.  Tanned  with  bark  they  constitute 
bazils,  and  are  used  for  making  slippers  and  as  bellows 
leather;  but  when  prepared  with  alum  and  salt,  or  with 
oil,  white  leather,  much  employed  for  aprons  and  by 
druggists,  chamois  leather  result.  A  good  many  are 
split,  the  upper  or  grain  side  being  tanned  with  sumach 
and  dyed,  then  worked  up  as  skiver,  roan,  and  morocco 
into  pocket-books,  hat-linings,  and  the  under  portion 
being  made  into  white  leather,  and  used  very  much  by 
the  chemist;  but  it  is  much  the  more  general  practice 
to  reserve  lamb-skins  for  the  latter  purpose  ;  sheep-skins 
are  sometimes  tanned  with  the  wool  adhering  to  them 
and  made  into  mats.  In  Asia  Minor  a  considerable 
trade  rises  from  the  preparation  of  lamb-skins  for  ladies’ 
glove-leather,  for  lining  of  morning  gowns,  for  slippers, 
and  for  winter  gloves.  On  the  hides  from  Asia  Minor 
the  wool  is  kept  for  the  purpose  of  retaining  the  warmth. 
Considerable  difference  may  be  observed  in  the  quality 
of  lamb-skins;  those  from  the  animals  killed  shortly  after 
being  born  are  possessed  of  a  very  fine  grain,  and  take 
a  very  uniform  dye.  The  same  qualities  are  in  a  great 
measure  retained  by  the  skins  till  a  month  old,  but  from 
this  period  they  begin  to  deteriorate.  In  the  southern 
part  of  France  and  in  Italy  great  numbers  of  lambs  are 
killed  averaging  four  weeks  old,  and  the  leather  pre¬ 
pared  and  employed  as  a  substitute  for  kid  leather. 

Goat-skins. — In  this  country  a  number  of  native  skins 


PROPER  TREATMENT  OF  HIDES  AND  SKINS. 


151 


are  used,  but  the  market  is  supplied  almost  entirely  by 
imported  goods,  more  especially  from  Switzerland,  Moga- 
dore,  the  Cape,  and  the  East  Indies.  The  Swiss  skins 
are  more  esteemed,  because  they  possess  a  close,  fine, 
and  equal  grain,  which  enables  the  dyer  to  give  them  a 
brilliant  and  permanent  hue ;  the  leather  is  also  stronger, 
and  weaves  better  than  any  other  manufactured  from 
goat-skins.  Mogadore  skins  are  made  into  a  kind  of 
black  morocco  leather,  which  still  goes  by  the  title  of 
Spanish  leather  or  cordovan,  in  consequence  of  the  first 
supplies  of  this  article  being  obtained  from  Spain  and 
Cordova,  where  the  Moors  originally  brought  the  manu¬ 
facture  to  great  perfection.  The  sound  skins  which 
arrive  from  the  Cape  of  Good  Hope  are  much  larger 
and  superior  in  strength  and  thickness  to  any  other 
variety.  East  India  skins  are  small  and  light,  and  are 
generally  converted  into  leather  chiefly  used  for  ladies’ 
shoes  and  upholstery.  Those  from  Mexico  known  as 
Tampico  skins  bear  a  very  high  character.  Compared 
with  sheep-skins,  those  of  goats  are  much  superior  in 
texture,  strength,  and  durability.  Goat-skins  are  occa¬ 
sionally  prepared  so  as  to  imitate  chamois  leather,  and 
applied  to  most  purposes  to  which  the  latter  is  adapted, 
and  likewise  with  the  hair  on  and  used  for  matting. 
Kid-skins,  manufactured  into  leather,  are  most  exten¬ 
sively  consumed  by  the  glover,  also  for  shoes,  binding 
leather  and  the  like. 

Deer-skins. — A  considerable  number  of  these  skins  are 
manufactured  into  chamois  leather,  and  also  into  glove 
leather. 

Hog  or  Pig-skins. — Tanned  pig-skin  constitutes  a  very 
porous,  light,  but,  nevertheless,  very  tough  and  valuable 
leather.  It  is  largely  used  by  harness-makers  for 
saddle  seats.  The  practice  of  skinning  pigs  is  followed 
in  Europe,  where  the  hide  is  dressed  with  the  hair  on 
and  used  to  cover  portmanteaus,  knapsacks,  etc., 

Seal-skins. — Of  these  a  great  quantity  is  imported 
yearly  into  France,  and  manufactured  into  upper  and 
varnished  leather.  They  are  obtained  from  the  animals 
captured  along  the  shores  of  North  America  for  their 


152 


CHEMISTRY  OF  TANNING. 


oil.  The  skin  of  the  seal  is  light,  but  of  a  close  texture, 
and  when  properly  tanned,  yields  a  leather  which  has 
greater  strength,  in  proportion  to  its  weight,  than  any 
other  variety.  Seal-skin  is  usually  made  into  black 
enamelled  leather  for  ladies’  shoes. 

Porpoise-skins. — The  skins  of  the  white  porpoise  have 
been  tanned  in  Canada,  and  the  leather  is  said  to  be 
soft,  strong,  and  possessed  of  a  beautiful  finish. 

Hippopotamus  Hides. — About  one  hundred  of  these 
skins  are  annually  imported  from  the  South  of  Africa, 
and  are  tanned  with  oak.  The  hide,  originally  of  great 
thickness,  assumes  the  appearance  of  boards  after  being 
tanned.  The  only  use  which  appears  to  be  made  of 
them  are  implements  used  for  beetling  in  washing,  and 
bleaching  cotton  and  linen  goods. 

Mode  of  Salting  Hides. 

Delande’s  method,  ^vhich  is  that  generally  employed, 
consists  in  laying  the  hides  open  upon  the  ground,  and 
sprinkling  the  flesh  side  with  salt,  more  liberally  at  the 
edges  and  on  the  spinal  portions  than  on  any  other  parts. 
They  are  then  folded,  or  doubled  lengthways,  down  the 
centre.  The  remaining  folds  are  made  over  each  other, 
commencing  with  the  shanks,  then  the  peak  of  the  belly 
upon  the  back,  afterwards  the  head  upon  the  tail  part, 
and  tail  part  upon  the  head,  and,  lastly,  by  doubling  the 
whole  with  a  final  fold,  and  forming  a  square  of  one  or 
two  feet.  This  being  done  they  are  then  piled  three 
and  “three  together,  and  left  until  the  salt  has  dissolved, 
and  penetrated  their  tissue,  which  generally  requires 
three  or  four  days.  Thus  prepared  they  are  sent  to 
market. 

Skins  may  be  dried,  even  after  having  been  salted, 
by  stretching  them  upon  poles  with  the  flesh  side  upper¬ 
most  and  exposing  them  to  dry  air  in  a  shady  place. 

Ten  pounds  of  salt  in  summer,  and  somewhat  less  in 
winter  are  requisite  for  each  skin  of  ordinary  size. 


PART  II. 

TANNING. 


SECTION  IY. 

PRELIMINARY  TREATMENT  OF  SKINS. 

Hides,  destined  to  be  tanned  and  transformed  into 
leather,  are  submitted  to  several  preliminary  operations 
before  being  tanned.  We  enumerate  them  successively. 
They  are  as  follows : — 

Washing  and  soaking. 

Swelling. 

Depilating . 

W orking  on  the  beam. 

Rinsing. 

Tanning. 


CHAPTER  XX. 

WASHING  AND  SOAKING. 

The  first  operation  that  the  skins  undergo  is  the 
washing  and  soaking.  It  is,  therefore,  convenient  to 
have  the  tannery  located  near  by  a  stream  of  water. 
The  skins  are  taken  in  a  green ,  dry.  or  salted  state.  The 
green  hides  are  those  from  recently  slaughtered  animals. 
They  are  soaked  in  water  for  half  a  day,  or  longer  if 
necessary,  so  as  to  remove  all  the  blood  and  adhering 
dirt.  They  are  to  be  well  raised  when  taken  out  from 
the  soaking.  If  they  are  to  be  soaked  for  a  long  time, 
it  is  necessary  to  handle  them  from  time  to  time. 

If  the  current  of  water  is  rapid,  trouble  will  be  saved 


154 


TANNING. 


by  planting  a  kind  of  rake  across  the  stream,  and  fast¬ 
ening  the  hides  so  that  the  friction  of  the  water  may 
loosen  the  dirt  and  carry  it  off.  The  skins  must  be  care¬ 
fully  suspended,  so  as  not  to  have  them  damaged  by 
rubbing  on  the  stones  at  the  bottom  of  the  stream. 

When  the  hides  are  dry  the  soaking  should  be  con¬ 
tinued  longer,  and  that  operation  is  facilitated  by  hand¬ 
ling  them  often,  and  stretching  them  each  time,  beating 
them  under  foot,  and  working  them  upon  the  wooden 
horse,  as  shown  in  Figure  28,  with  the  fleshing  knife 
Figure  29,  and  then  leaving  them  to  drain.  The  fleshing 
is  repeated  once  or  twice. 


The  working  and  scraping  are  continued  until  all  ani¬ 
mal  matters  which  are  prone  to  putrefaction  are  removed. 
The  length  of  time  cannot  be  prescribed.  The  hides  are 
to  remain  in  water  until  they  have  become  supple,  and 
it  is  for  the  intelligence  of  the  workman  to  determine 
when  this  point  is  attained.  If  the  soaking  is  too  long, 
the  skins  have  a  tendency  to  putrefy.  Dried  and  salted 
hides  require  a  much  longer  soaking  than  those  which 
have  been  only  dried. 

The  working  and  softening  of  the  hides  upon  the 
horse  or  beam  are  considered  indispensable  operations 
by  every  experienced  tanner. 

When  the  skins  have  all  been  soaked  and  washed,  and 
are  sufficiently  supple,  they  are  returned  and  left  in  the 
water  for  six  hours.  In  running  water  they  may  remain 
eight  hours.  Reference  is  here  made  exclusively  to  large 
hides,  for  cowskins  may  be  left  without  danger  for  24 
hours,  and  calf-skins  48  hours,  being  careful  to  observe 


WASHING  AND  SOAKING. 


155 


the  nature  of  the  water  and  the  temperature  of  the  air. 
Too  long  soaking  in  the  same  water  exposes  the  skins 
to  the  danger  of  putrefaction,  and  the  rapidity  of  the 
decomposition  is  proportional  to  the  amount  of  filthy 
matters  contained  in  the  water. 

Well-salted  skins,  but  not  dried,  may  be  cleansed  in 
48  hours,  but  they  can  be  left  to  soak  three  or  four  days 
without  danger.  They  must  be  withdrawn  once  a  day, 
left  to  drain  two  hours,  worked  with  the  back  of  the  flesh¬ 
ing  knife  and  well  rinsed  in  water.  The  object  of  those 
manipulations  is  to  remove  salt  and  dirt,  and  render 
them  soft  and  supple.  When  taken  out  from  the  water 
for  the  last  time  give  a  vigorous  and  thorough  rinsing. 

At  St.  Saens  they  commonly  use  dry  hides  from  South 
America,  which  are  placed  directly  in  vats  filled  with 
lime-water  and  left  for  six  or  ten  days,  care  being  taken 
to  work  them  in  the  usual  manner  at  frequent  intervals 
during  the  soaking.  These  vats  are  8  feet  long  and  5 
feet  wide. 

The  skins  are  softened  by  the  action  of  lime  and  ren¬ 
dered  more  easy  to  be  handled.  At  this  stage  the  de¬ 
fective  parts  may  be  detected,  and  sometimes  they  are 
so  damaged  as  to  be  suitable  only  to  manufacture  glue. 

At  Liege,  where  they  mostly  use  the  dry  hides  from 
Brazil  and  Caraccas,  there  is  no  allotted  time  for  soak¬ 
ing.  After  four  or  five  days  they  examine  each  vat,  and 
withdraw  such  hides  as  have  become  soft  and  leave  the 
rest.  This  process  is  repeated  daily  until  all  the  hides 
have  been  withdrawn. 

As  soon  as  the  hides  are  taken  from  the  vats,  they  are 
worked  upon  the  horse  and  then  returned  to  the  water. 
On  the  following  day  they  are  thoroughly  rinsed  and 
placed  in  the  drying  room.  The  working  is  solely  for 
the  purpose  of  removing  the  wrinkles  and  stiffness  of 
the  dry  skins.  These  manipulations  are  unnecessary  for 
green  hides. 

According  to  some  tanners  the  quality  of  the  leather 
is  improved  in  proportion  to  the  duration  of  the  soaking 
of  the  hides ;  but  it  is  undeniable  that  when  it  exceeds 


156 


TANNING. 


a  certain  time  the  skin  acquires  a  tendency  to  decompo¬ 
sition,  and  the  quality  of  the  leather  is  impaired. 

Soaking  of  Foreign  Hides. — Before  we  speak  of  this 
soaking  we  must  say  a  word  or  two  regarding  the  em¬ 
ployment  of  sulphuret  of  arsenic.  This  substance  is 
produced  by  passing  a  current  of  hydrosulphuric  acid 
through  a  solution  of  arsenic.  The  sulphuret  is  pre¬ 
cipitated  in  the  form  of  a  bright-yellow,  flaky  substance. 

By  mixing  the  orpiment  with  a  solution  of  lime  in 
the  proportion  of  4  parts  of  the  former  to  96  parts  of 
the  latter  a  compact  mass  may  be  obtained  which  is 
easily  used  for  depilating  purposes. 

Small  hides  or  kips,  after  being  well  washed  and 
cleaned,  are  soaked  by  laying  them  in  foul  bloody  water. 
This  method,  which  is  of  universal  use  amongst  white 
tanners,  requires  much  attention,  like  every  other  pro¬ 
cess  by  means  of  which  the  hide  is  almost  restored  to  its 
original  condition.  It  imparts  a  perfect  softness  to  the 
hide,  leads  rapidly  to  the  result,  and  is  not  costly ;  but 
it  requires  the  greatest  precautions.  The  method  to 
which  we  give  the  preference  is  the  one  that  we  now 
propose  to  mention  as  offering  certain  guarantees,  as  we 
have  lately  had  proven  to  us  by  actual  experiment.  This 
method  is  the  softening  of  the  hide  by  sweating,  that  is 
to  say,  heating  it  without  fire  and  without  steam. 

The  sweating  pit  is  a  pit  about  12  feet  long  by  7|  feet 
broad  and  6  feet  deep,  flat  on  the  top.  In  order  to  se¬ 
cure  the  desired  result  it  should  be  constructed  of  good 
masonry,  and,  when  practicable,  built  under  ground. 
Moreover  attention  should  be  given  to  have  the  access 
of  the  air  removed  as  much  as  possible  from  the  entrance 
to  the  pit.  The  door,  which  should  be  5  feet  high  by 
20  feet  broad,  must  be  made  of  strong  pine  wood  and 
furnished  with  three  bars  strongly  fixed,  so  that  it  may 
be  made  air-tight  when  closed,  and  not  warp  from  the 
effect  of  the  dampness  which  fermentation  produces. 
The  sweating  vat  should  contain  poles  planted  in  the 
ground  at  intervals  of  about  If  feet,  according  to  the 
breadth  of  the  vat,  and  rise  to  the  height  of  5|  feet.  It 
is  important  to  observe  these  instances  as  nearly  as  can 


WASHING  AND  SOAKING. 


157 


be,  for  if  the  sweating  vat  is  too  large,  the  same  effect 
will  not  be  produced.  For  sole-leather  it  is  more  de¬ 
sirable  to  use  two  smaller  sweating  vats  than  one  very- 
large  one. 

Small  hides  or  kips  should  be  thoroughly  washed  in 
very  clean  water,  spread  out  after  four  days’  soaking, 
well  rinsed  and  drained,  then  laid  together  in  packs  in 
such  a  manner  that  the  hair  is  outward,  and  the  pairs 
of  skins  back  to  back.  Hang  them  over  the  poles  of  the 
sweating  vat,  with  the  tail  end  upon  one  side,  and  the 
head  on  the  other.  Then  close  the  door  and  stop  it  up 
well  so  that  the  air  may  be  excluded  as  much  as  possi¬ 
ble,  and  leave  matters  thus  until  the  odor  of  the  sweat¬ 
ing  process  becomes  quite  strong,  which  is  an  indication 
that  the  process  of  depilation  is  about  to  begin. 

The  working  of  the  sweating  process  is  shown  by  a 
sharp  lye  which  forms  under  the  hair,  and  which  drops 
off  the  instant  fermentation  sets  in.  After  taking  the 
skins  out,  the  thick  portions  should  be  worked  with  an 
iron  instrument,  then  lay  the  hides  in  water  and  let 
them  soak  for  a  day  or  two,  after  which  the  flesh  side 
should  be  worked  with  the  stretching  iron,  in  order  to 
bring  out  the  grain  again  before  consigning  them  to  the 
lime  pit. 

Strange  as  this  treatment  of  the  hair  side  may  appear, 
we  do  particularly  recommend  it,  for  in  order  to  restore 
a  cow-hide  to  its  primitive  condition,  it  is  not  sufficient 
to  attend  to  the  flesh  side  alone ;  we  require  to  provide 
against  the  remaining  of  wrinkled  places  on  the  grain, 
as  often  happens,  especially  in  Java  and  Calcutta  hides. 
When  we  come  to  dress  the  leather,  these  cannot  be 
removed  by  the  grainer  or  stretching  iron,  because  we 
have  neglected  to  give  sufficient  care  to  the  grain. 

We  cannot  too  often  repeat  that  light  hide  should 
not  be  placed  in  too  strong  lime ;  this  sort  of  hides 
should  rather  be  operated  upon  by  degrees  and  always 
with  weak  lime,  and,  for  this  reason,  it  appears  to  us 
that  the  surest  method  that  can  be  followed  in  order  to 
secure  a  successful  result,  is  to  use  lime  that  has  already 
been  weakened  by  contact  with  fresh  hides.  For  a  dry 


158 


TANNING. 


hide,  when  acted  upon  by  lime,  may  be  compared  to  a 
flower,  wThich  is  taken  out  of  a  warm  forcing-house,  and 
exposed  to  a  cold  temperature.  It  will  be  seen  that  its 
development  will  be  arrested,  it  will  shrink  and  draw 
together,  and  never  will  expand  any  further.  The  com¬ 
parison  may  be  incomplete,  but  yet  it  is  apt. 

With  regard  to  the  large  hides  of  wild  animals,  such 
as  those  imported  from  La  Plata  and  elsewhere,  whether 
dried  fresh  or  dry  salted,  we  urgently  recommend  that 
they  should  be  subjected  to  the  sweating  process,  for,  we 
repeat  it,  the  sweating  system  has  not  only  the  effect 
of  facilitating  the  process  of  depilation,  but  of  giving  to 
dry  wild  hides  that  development  of  which  they  stand  in 
need. 

The  sweating  process,  as  we  understand  it,  regulates 
and  hastens  the  expansion  of  the  hide,  opens  the  pores, 
and  places  the  hide  in  a  state  similar  to  that  in  which 
it  was  at  the  time  the  animal  was  slaughtered.  To  pre¬ 
pare  it  for  the  leather  dressing  process,  it  will  be  found 
enough  to  work  the  hide  lightly  on  the  flesh  side  with 
the  iron,  when  it  is  taken  out  of  the  sweating  vat,  so  as 
to  stretch  out  the  wrinkles  that  may  appear  before  the 
hide  is  placed  in  the  lime  pit,  which,  as  has  been  said, 
should  always  first  contain  a  weakened  lime  bath. 

It  is  now  for  us  to  say  something  as  to  heavy  hides, 
and  it  is  necessary  to  state  that  we  restrict  ourselves  to 
the  consideration  exclusively  of  foreign  hides,  i.  e the 
hides  of  wild  animals. 

We  will  begin  with  dry  hides,  those  coming  from 
Buenos  Ayres,  for  instance,  as  being  the  best  known. 
What  is  considered  the  most  estimable  property  of  Bue¬ 
nos  Ayres  hides'?  That  they  are  a  species  of  hide  which 
softens  easily  and  in  a  regular  manner.  It  is  admitted 
that  hides  which  are  allowed  to  remain  continuously  in 
water  soften  less  readily  than  those  which  are  alternately 
soaked  and  piled.  And  now  let  us  consider  how  piling 
compares  with  sweating.  Piling  is  nothing  more  or  less 
than  a  slow  inward  sweating,  and  while  it  is  slow  you 
run  the  risk  of  having  the  edges  damaged,  by  giving  the 
time  necessary  to  effect  a  good  result.  80  in  order  to 


WASHING  AND  SOAKING. 


159 


save  the  back  and  extremities  you  are  obliged  to  dispense 
with  a  complete  softening  of  the  hide,  and  moreover  lose 
time.  This  is  always  the  result  of  irregular  soaking. 
Now  what,  in  fact,  do  we  seek  to  attain  in  soaking  the 
hide!  Simply  the  raising  up  of  the  fibres,  in  order  to 
save  those  parts  of  the  hide  which  were  wet,  and  became 
dried  during  its  transportation ;  and  we  believe  the  best 
mode  of  doing  this  consists  in  accelerating  the  operation, 
so  as  to  obtain  a  thorough  soaking  by  the  sacrifice  of 
from  seven  to  eight  days. 

Moreover,  stagnant  and  hard  water  does  not  give  the 
dry  hide  time  to  become  completely  softened  again,  at  * 
least  it  injures  the  grain,  which  becomes  lost  before  the 
water  has  had  time  to  penetrate  the  fibres  of  the  hide. 

Under  these  circumstances,  sweating  is  alone  of  use, 
and  if  necessary,  a  softening  during  24  hours  in  open 
water  will  be  sufficient  to  secure  a  satisfactory  result,  as 
experiment  has  proven. 

Soak  the  hides  in  water  for  24  hours,  mark  the  flesh 
side  well,  and  rinse  the  hair  side  thoroughly,  so  as  to  rid 
it  of  all  foreign  substances,  so  that  no  faulty  spots  may 
ensue;  let  them  drain  in  a  heap  during  four  or  five  hours, 
and  bring  them  to  the  sweating  process  as  above  de¬ 
scribed.  Sprinkle  them  with  fresh  water  through  a 
gardener’s  watering-pot,  provided  with  a  sieve-like  spout, 
and  after  the  hides  have  been  again  allowed  to  drain  oft*, 
put  them  back  in  the  sweating  vat. 

Three  sprinklings  with  the  watering-pot  will  be  found 
ample,  in  combination  with  the  sweating  process,  to  soften 
the  driest  and  oldest  hides  to  such  a  degree,  that,  even 
if  they  are  of  the  heaviest,  they  can  at  once  be  divested 
of  the  hair.  Then  separate  them  after  rinsing  them,  lay 
them  again  in  running  water,  clean  and  scrape  them,  and 
do  not  interrupt  the  gradual  course  which  the  hide  has 
to  undergo. 

What  we  have  last  mentioned  should  only  be  resorted 
to  when  suitable  water  is  wanting  for  proper  soaking, 
for  we  recommend  above  all  things  that  the  hide  be  care¬ 
fully  soaked  in  water,  as  this  raises  it  well,  but  in  all 
cases,  whichever  mode  of  soaking  be  followed,  the  hides 


160 


TANNING. 


should  never,  as  a  general  rule,  be  allowed  to  stay  in  the 
water  longer  than  four  days,  or  from  five  to  six  days  in 
severely  cold  weather.  Of  course  the  sprinkling  with  a 
watering-pot  is  then  superfluous,  and  there  will  then 
only  remain  the  piling  up  of  the  hides  in  the  sweating 
vat  to  be  attended  to.  They  should  be  left  in  it  from 
four  to  six  days,  according  to  the  season  of  the  year. 

With  regard  to  salted  wild  hides,  a  proper  softening 
in  water  will  do,  and  this  water  should  be  changed  every 
now  and  then,  so  that  the  hide  does  not  remain  long  in 
briny  water,  and  care  should  be  taken  to  rinse  them 
thoroughly  before  placing  them  in  the  fresh  water ;  for 
the  rest  the  same  course  is  to  be  pursued  as  with  dry 
hides. 


CHAPTER  XXI. 

INFLUENCE  OF  THE  WATER  UPON  THE  QUALITY  OF  THE 

LEATHER. 

It  is  a  mooted  point,  whether  the  nature  of  the  water 
used  for  soaking  has  any  influence  upon  the  quality  of 
the  leather.  No  positive  experiments  have  been  made 
yet,  but  in  this  case  we  think  that  it  is  better  to  take 
the  affirmative  side  of  the  question.  Calf-skin  leather, 
which  should  be  soft  and  supple,  requires  soft  fresh  water, 
and  it  will  be  difficult  to  manufacture  them  with  hard 
water. 

Modern  chemists  call  water  protoxide  of  hydrogen. 
When  pure  it  is  inodorous,  colorless,  transparent,  elastic, 
a  good  conductor  of  heat  and  electricity.  It  boils  at  212°, 
and  freezes  at  32°.  The  waters  called  soft  dissolve  soap, 
while  those  which  do  not  possess  this  property  are  called 
hard.  The  former  is  nearly  free  from  soluble  matters, 
while  the  latter  contains  calcareous  and  other  salts.  The 
composition  of  chemically  pure  water  is  in  weight — 

■  Equiv. 

Oxygen  .  .  .  .  .  1  =  8  =  88  88 

Hydrogen  .  .  .  .  1  =  1  =  11. 22 

9  iOO.OG 


INFLUENCE  OF  THE  WATER  UPON  THE  LEATHER.  161 

The  agreeable  taste  of  pure  water  is  due  to  the  air  it 
contains ;  when  expelled  by  ebullition  it  is  insipid. 

Rain  Water. — -The  purest  rain  water  is  that  which 
falls  in  the  country  where  there  are  no  noxious  emana¬ 
tions. 

The  soluble  impurities  of  rain  water  are  those  which 
it  has  dissolved  from  the  atmosphere,  and  consist  of 
minute  traces  of  chloride  of  sodium,  carbonic  acid, 
and  carbonate  of  ammonia.  After  a  thunder-storm,  rain 
water  contains  small  traces  of  nitric  acid  formed  by  the 
atmospheric  electricity. 

Snow  Water. — This  water  is  the  same  as  rain,  only  it 
is  crystallized,  and  by  this  crystallization  it  loses  the 
gases  held  in  solution. 

Spring  Water. —Water,  in  its  transit  through  the  soil, 
becomes  charged  with  such  constituents  thereof  as  are 
soluble  in  it ;  and  consequently,  the  purity  of  the  water 
is  proportional  to  the  insolubility  of  the  earth  through 
which  it  has  flowed. 

The  purest  spring  waters  contain  air,  carbonic  acid, 
and  minute  quantities  of  hydrochlorate  and  carbonate 
of  soda. 

River  Water. — There  is  not  much  difference  between 
river  and  spring  water.  Sometimes,  however,  it  is  purer 
from  having  deposited  its  suspended  matter,  and  also  a 
part  of  that  held  in  solution,  which  generally  happens 
when  it  traverses  a  long  and  silicious  bed.  If  it  pass 
over  or  through  limestone,  or  other  strata  containing 
soluble  ingredients,  it  becomes  less  pure. 

Lake  Water. — Lake  water  contains  more  soluble 
principles  of  the  soil  upon  which  they  rest  than  river 
water;  this  condition  is  promoted  by  their  state  of 
quiescence. 

Marsh  Water. — This  kind  is  in  a  more  permanent 
state  of  stagnation  than  lake  water.  This  water,  on  ac¬ 
count  of  the  organic  matters  it  contains,  easily  enters 
into  a  state  of  putrefaction. 

Well  Water  contains  more  soluble  constituents  of 
the  soil  than  lake  water.  Well  water  is  generally  hard , 
because  among  earthy  salts  it  contains  particularly  sul- 

11 


162 


TANNING. 


phate,  bicarbonate,  and  chloride  of  lime,  which  render 
soap  insoluble  in  it. 

Well  water,  in  the  vicinity  of  the  sea,  has  a  brackish 
taste,  and  contains  the  same  constituents  as  sea  water. 

When  well  water  is  very  hard  the  addition  of  a  little 
carbonate  of  soda  will  decompose  the  lime  salt  and  ren¬ 
der  it  potable. 

By  what  has  been  said  it  is  evident  that  rain  water  is 
the  purest,  but  all  drinkable  waters  are  applicable  for 
tanning  purposes.  To  soften  hard  waters  the  French 
tanners  add  a  solution  of  pigeon  or  chicken  dung  to  the 
vat,  and  stir  it  thoroughly  by  means  of  a  shovel.  The 
hides  are  then  put  into  it  to  soak.  Some  tanners,  in¬ 
stead  of  washing  in  the  river,  soak  them  in  troughs. 
Water  containing  iron  renders  the  leather  brittle  and 
blackens  the  hide. 

In  Paris,  the  water  is  purified  by  filtering  it  through 
spent  tan.  There  is  a  series  of  three  vats,  charged 
similarly  with  spent  tan  ;  and  as  the  water  which  is 
poured  into  the  first  vat  is  drawn  through  a  cork  at  the 
bottom  it  is  transferred  to  the  second,  and  afterwards  to 
the  third.  As  thus  rectified,  it  contains  a  little  tannin 
derived  from  the  spent  tan,  which  renders  it  particu¬ 
larly  adapted  for  the  early  part  of  the  tanning  operation. 

Some  waters  are  preferable  to  others  for  tanning,  but 
on  what  particular  quality  of  the  water  this  superiority 
depends  has  not  yet  been  determined.  The  safest  way 
is  to  prefer  those  which  contain  the  less  soluble  matters, 
particularly  earthy  salts,  for  they  certainly  reduce  the 
tanning  powers  of  the  ooze  by  combining  with  some  of 
its  constituents. 

The  suspended  matters,  consisting  of  mud,  as  well  as 
the  soluble  organic  matters,  which  impart  to  water  a 
bad  taste,  may  be  removed  by  filtering  the  water  through 
clean  gravel  and  fresh  charcoal. 

If  the  lime  exists  in  the  state  of  bicarbonate,  it  can 
be  separated  by  adding  to  the  water  some  lime-water. 
Boiling  produces  the  same  result. 


SWELLING  OR  RAISING  OF  THE  HIDES. 


163 


CHAPTER  XXII. 

SWELLING  OR  RAISING  OF  THE  HIDES. 

The  second  process  to  which  hides  are  to  be  subjected 
is  termed  raising ,  and  is  that  by  which  the  pores  are  dis¬ 
tended,  the  fibres  swollen,  and  the  hair  loosened.  These 
results  are  effected  by  means  of  alkaline  or  acid  solutions, 
and  by  fermentation.  Milk  of  lime  is  the  alkaline  liquor 
generally  employed.  Lime-water  has  been  proposed  as 
a  substitute,  but  it  is  less  permanent  in  its  action,  and 
requires  frequent  renewal  in  order  to  insure  the  perfect 
cleansing  of  the  hides. 

Lime  Process. — This  process,  which  is  the  oldest,  is 
the  most  defective,  but  in  a  complete  work  on  tanning 
it  is  necessary  to  speak  of  it.  It  is  an  ascertained  fact 
that  the  object  of  the  vat  work  is  to  effect  the  swelling 
of  the  hide,  to  open  its  pores,  and  dispose  them  to  the 
depilatory  operation  and  absorption  of  the  tannin.  The 
tanner  must  be  perfectly  aware  that  he  could  never 
make  a  good  leather  with  a  hide  which  has  not  been 
welljrrepared  in  the  vats. 

The  vats  are  prepared  in  two  ways  :  they  are  of  wooden 
work  sunk  in  the  ground  or  masonry.  The  vats  des¬ 
tined  to  swell  the  hides  to  facilitate  the  depilation  and 
raising  are  more  or  less  large  ;  they  are  square  or  round, 
about  4i  feet  square  and  of  the  same  depth.  The  num¬ 
ber  of  hides  determines  ordinarily  the  quantity  of  lime 
necessary  for  each  vat;  one  peck  is  usually  sufficient  for 
a  large  hide,  while  under  some  circumstances  it  is  neces¬ 
sary  to  increase  the  quantity.  In  several  manufactures 
to  economize  lime,  they  add  ashes,  pigeon,  or  dog  dung, 
but  we  advise  tanners  to  reject  such  processes. 

To  make  a  new  vat  throw  in  it  quick-lime,  cover  it 
with  water  and  stir  well  with  a  stirrer,  as  represented 
in  Fig.  30,  till  slacked  and  reduced  into  milk. 

This  operation  done,  leave  a  few  days  and  it  is  then 
ready  to  receive  the  hides. 

The  vats  are  distinguished  as  dead,  weak ,  and  live  vats . 


164 


TANNING. 


The  dead  vat  is  that  which  has  been  nearly  exhausted 
of  its  strength ;  the  weak  is  that  which  has  only  been 
used  long  enough  to  deprive  it  of  a  portion  of 
Fig.  BO.  its  force,  and  the  live  vat  is  that  which  has  not 
n  yet  been  worked. 

It  is  easy  to  understand  that  the  live  vat  be¬ 
comes  successively  the  weak  and  the  dead  vat. 
When  a  tanner  uses  more  than  three  vats  he 
establishes  between  the  dead  and  live  vats  as 
many  middling  terms  vats  as  convenient.  The 
whole  of  the  vat  is  called  raising  series. 

The  raising  should  be  commenced  in  the 
L  dead  vat,  and  continued  in  consecutive  order 
through  the  series  to  the  live  vat.  In  some 
factories  the  series  consist  of  as  many  as  twelve 
vats ;  and  in  this  case  there  should  be  a  graduation  in 
the  strength  of  the  liquors.  The  duration  of  this  opera¬ 
tion  varies  in  different  localities.  Some  tanners  leave 
their  hides  for  three  months,  while  others  soak  them 
for  eighteen  months. 


Fig.  31. 


There  is  great  variation  in  the  composition  of  the 
vats.  In  Auvergne  and  Limousin  they  mix  with  the 
lime,  ashes,  or  lye  of  ashes,  and  in  some  other  places  the 
lime  forms  only  one-fourth  in  the  composition  of  the  vats. 
The  old  manufacturers  gave  the  hide  a  soaking  of  ten, 
twelve,  and  even  fifteen  months;  and  then  when  they 
have  became  sufficiently  softened,  transferred  them  to  a 
dead  vat  for  eight  days;  at  the  end  of  which  time  they 


SWELLING  OR  RAISING  OF  THE  HIDES. 


165 


were  withdrawn,  hung  up  for  eight  days,  and  again  placed 
in  the  same  vat  for  eight  more  days,  etc. 

These  consecutive  operations  are  thus  continued  for 
two  months  or  until  the  hair  can  be  readily  detached. 

The  graduation  of  tile  vat  varies  in  different  localities. 
In  Angoumois  it  consists  of  twelve  vats;  the  first  two 
are  dead ,  the  four  following  weak,  and  the  last  six  fresh 
or  live. 

In  Poitou  it  consists  of  six  vats ;  the  first  two  are  dead 
vats  and  the  last  three  live  vats. 

In  Britanny  many  tanners  who  believe  that  the  hides 
are  raised  better  with  the  hair  on  than  in  pelt,  give  six 
live  vats  and  do  not  remove  until  the  fourth  and  even 
the  fifth  vat. 

In  Auvergne  they  give  three  raisings  of  a  month  each 
with  a  mixture  of  lime  and  alkaline  lye. 

So  many  vats  are  useless ;  generally  speaking,  three 
or  four  vats  skilfully  managed  suffice  for  any  kind  of 
skins.  Some  have  asserted  that  ten  to  twelve  months 
are  requisite  for  a  thorough  soaking ;  but  the  experience 
of  good  tanners  proves  that  two  months  are  sufficient. 

According  to  Curaudau  only  ten  or  twelve  days  are 
required  for  the  transit  of  the  hides  through  the  three 
lime  vats.  He  thinks  a  longer  time  will  be  useless,  and 
that  the  shorter  the  soaking  the  greater  is  the  weight 
acquired  by  the  hides  in  tanning. 

Malepeyre  says  it  is  now  established- — 1st.  That  it  is 
sufficient  to  leave  the  hides  in  the  pits  for  twenty-four 
hours,  and  an  equal  length  of  time  in  stack.  2d.  That 
this  operation  should  not  continue  for  more  than  six  or 
eight  weeks.  3d.  That  three  or,  at  most,  four  good  vats 
are  sufficient.  4th.  That  after  this  interval  the  hides 
are  easily  cleansed,  and,  on  the  other  hand,  where  the 
treatment  is  prolonged  the  hides  become  parched.  5th. 
That  after  three  or  four  pits,  the  hides  will  have  swollen 
to  the  fullest  extent,  and  finally  there  is  a  great  waste  of 
time,  lime,  and  materials  in  the  old  method  of  steeping 
from  ten  to  fifteen  months. 


166 


TANNING. 


CHAPTER  XXIII. 

STACKING  OP  THE  HIDES. 

Stacking  is  to  pile  the  hides  one  upon  the  other  on 
the  side  of  the  vat  as  they  are  drawn  from  it,  and  leave 
them  remaining  a  shorter  or  longer  time  before  returning 
them  to  the  bath  for  another  wetting. 

Piling  enables  the  working  of  60  hides  in  a  vat  of 
a  capacity  for  thirty,  by  having  one  bath  taking  the  place 
of  the  other  in  alternate  operations.  While  one  set  of 
thirty  is  in  retreat  the  other  should  be  in  the  vats,  and 
vice  versa. 

The  vats  should  be  covered;  and  as  the  skins  in  re¬ 
treat  are  susceptible  of  becoming  hard  by  exposure  to 
the  sun  and  air,  they  should  not  be  kept  in  that  state 
longer  than  is  necessary.  At  every  handling  the  water 
and  lime  at  the  bottom  should  be  thoroughly  stirred, 
and  a  workman  at  each  end  of  the  vat,  by  the  aid  of 
tongs,  arranges  the  hides  in  it  so  that  they  may  be 
smooth  and  firm.  The  suspended  lime  soon  subsides 


Fig.  32. 


upon  the  hides,  and  the  supernatant  liquor  which  should 
cover  the  hides  to  a  depth  of  some  inches  will  be  clear 
and  transparent.  As  the  greater  portion  of  the  lime  is 
in  contact  with  the  skin  at  the  bottom  of  the  vat,  its 
action  is  more  powerful  on  them  than  on  those  above; 
and  consequently  in  recharging  the  vat  after  stacking, 
the  order  should  be  reversed. 


STACKING  OF  THE  HIDES. 


167 


Should  the  vat  become  too  weak  to  produce  the 
desired  effect,  it  must  be  strengthened  by  the  addition 
of  the  quantity  of  lime  necessary  to  restore  its  force. 
The  advantage  is  thus  obtained  of  giving  the  hide  the 
benefits  of  two  vats  in  one.  The  lime  should  be  added 
while  the  skins  are  out  of  the  vat. 

To  remove  the  hairs,  the  scraping  knife  alone  is  used. 
It  is  a  dull-edged  instrument  which  is  not  liable  to 
damage  the  skin  by  cutting  it,  while  it  is  all  efficient  in 
scraping  off  the  hair.  It  is  a  bad  practice  to  use  the 
slate  or  rubber,  which,  being  rough, 
may  scratch  and  damage  the  hide 
upon  its  grain  side. 

The  use  of  sand,  ashes,  etc.,  for  re¬ 
moving  the  hair  is  very  improper ;  it  is  also  a  bad  prac¬ 
tice  to  wait  until  the  completion  of  the  soaking  before 
scraping  off  the  hair,  because  the  lime  will  in  time  act 
on  the  hair  itself. 

When  the  hair  is  removed,  rinse  the  skins  and  re¬ 
place  them  in  the  dead  vat,  and  -so  on.  It  suffices  to 
leave  the  hides  for  fifteen  days  in  each  of  these  vats, 
but  care  must  be  taken  to  stack  and  replace  them  every 
twenty-four  hours. 

M.  Tournal  says :  “  The  force  of  habit  and  perhaps 
the  use  of  the  Kermes  oak  causes  many  tanners  to  con¬ 
tinue  the  use  of  lime.  But  if,  in  rinsing,  great  care  is 
not  taken  to  remove  every  trace  of  lime,  the  minute 
traces  remaining  will,  by  abstracting  carbonic  acid  from 
the  air,  become  insoluble  and  render  the  skin  dry,  brittle, 
and  perhaps  useless.  These  faults  are  not  entirely  due 
to  the  carbonic  acid  of  the  air,  but  also  to  the  formation 
of  tannate  of  lime  and  of  stearate  and  oleate  of  the  same 
basis  which  are  generated  by  the  presence  of  fatty  mat¬ 
ters  existing  in  the  hides. 

“  Tanners  who  use  the  Kermes  pretend  that  its  warm 
nature  imparts  stiffness  to  the  leather,  and  that  the  only 
available  mode  of  raising  is  by  lime.  They  own  that 
the  sour  tan  juice  and  barley  processes  distend  the  pores 
of  the  hides  much  more  than  lime,  and  that  the  tanning 
principle  of  the  Kermes  having  a  tendency  to  combine 


168 


TANNING. 


rapidly  with  the  hide  imparts  an  unnatural  stiffness  to 
the  leather.” 

To  the  above  statement  we  will  add  that  the  bark  of 
Kermes  oak  is  richer  in  tannin  than  the  ordinary  oak, 
and  admirable  leather  may  be  prepared  by  tanning  with 
it  skins  which  have  been  raised  by  sour  tan  liquor. 


CHAPTER  XXIV. 

INCONVENIENCE  OF  THE  LIME  PROCESS. 

The  inconveniences  of  the  lime  process  are  the 
following : — 

1st.  The  contact  of  caustic  lime  alters  more  or  less 
the  texture  of  the  hide,  and  permitting  it  to  penetrate 
the  pores,  it  remains  in  them  in  the  state  of  caustic 
lime,  carbonate,  or  lime  soap. 

2d.  The  rinsings  in  water  and  the  workings  remove 
it  only  partially,  which  is  an  impediment  to  perfect 
tanning. 

3d.  It  hinders  the  ready  penetration  of  the  tan  liquor, 
and  the  perfect  combination  of  tannin  with  the  skin,  and 
so  obstinately  resists  removal  during  all  manipulations 
that  a  portion  is  always  found  in  the  best  leather.  • 

The  experiments  of  Dr.  J.  Davy*  show  that  the  action 
of  lime  upon  animal  texture  is  rather  antiseptic  than 
destructive.  Its  corroding  influence  is  limited  to  the 
cuticle,  hair,  nails,  and  all  gelatinous  tissues.  These 
latter  become  soft  and  gelatinous  owing  to  a  combina¬ 
tion  which  they  form  with  lime,  for  on  analyzing  the 
ash  of  the  cuticle  thus  treated  a  large  increase  of  its 
normal  contents  of  that  earth  was  obtained. 

The  matters  were  steeped  in  milk  of  lime,  kept 
caustic  in  close  vessels,  by  the  entire  exclusion  of  air. 
After  treatment  they  cease  to  be  putrescent. 

These  disadvantages  have  led  to  the  substitution  of 
other  agents,  which  we  will  proceed  to  treat  of  in  the 
following  chapters. 


*  Chemist,  1850. 


METHOD  OF  RAISING.  BY  ACIDS. 


169 


CHAPTER  XXV. 

METHOD  OF  RAISING  BY  ACIDS. 

An  acid  liquor  has  been  used  by  some  tanners  instead 
of  milk  of  lime.  The  Kalmucks  use  sour  milk  for  this 
purpose.  Pfeiffer  has  proposed  the  acidulated  water 
obtained  by  the  distillation  of  lime  and  peat.  Some¬ 
times  a  little  sulphuric  acid  is  added.  This  acid  in  a 
dilute  state,  as  also  all  vegetable  acids,  produces  the 
same  effect.  Acids  have  the  double  advantage  of  loosen¬ 
ing  the  hair  and  swelling  the  hide. 

Some  tanners  soften  the  skins  by  sprinkling  one  half 
with  salt,  and  folding  the  other  half  over  it ;  then  they 
are  piled  and  covered  with  straw.  The  fermentation 
follows ;  they  must  be  turned  several  times  daily,  until 
they  have  attained  that  state  in  Vvhich  they  can  be  easily 
depilated.  The  use  of  salt  is  not  necessary.  They  are 
to  be  piled  on  a  bed  of  straw  and  covered  in  like  manner. 
Twenty-four  hours  after  they  are  turned  and  examined 
twice  daily,  so  as  not  to  exceed  the  proper  point.  In 
some  places  the  hides  are  imbedded  in  horse  manure,  in 
others  they  are  covered  with  tan.  The  same  effect  could 
be  produced  by  suspending  the  hides,  which  have  been 
left  lying  in  a  heap  for  several  days,  in  a  close  room 
kept  above  the  ordinary  temperature  by  a  smouldering 
tan  fire. 

All  methods  of  fermentation  are  termed  sweating  pro¬ 
cesses.  But  whatever  is  the  process  followed,  the  skins 
are  to  be  spread  upon  a  wooden  horse,  and  scraped  with 
a  dull  edged  knife,  as  soon  as  the  hair  begins  to  yield 
readily.  In  this  manner  the  hair  and  outer  skin  are 
fleshed  or  scraped  off.  The  outer  skin  being  of  a  differ¬ 
ent  nature  from  that  of  the  hide,  and  not  uniting  with 
tannin,  must  be  removed  in  order  to  allow  the  free  pas¬ 
sage  of  the  tan  liquor  through  the  skin,  and  to  facilitate 
the  tanning  process. 


170 


TANNING. 


CHAPTER  XXVI. 

DEPILATION  BY  STEAM. 

In  many  places,  instead  of  a  milk  of  lime,  they  use 
another  method,  which  consists  in  submitting  the  hides, 
in  the  heap,  to  a  slight  putrefactive  fermentation  in 
heated  chambers.  In  summer  it  is  difficult  to  control 
this  fermentation,  and  sometimes  it  is  necessary  to  salt 
the  hides.  After  some  days  the  epidermis  becomes  loose 
and  detached,  and  may  be  readily  scraped  off  from  the 
hair. 

Mr.  Robinson,  of  Delaware,  uses  steam  as  the  heating 
medium,  in  an  arched  chamber  eighteen  feet  long,  ten 
feet  high,  and  ten  feet  in  breadth,  and  lined  interiorly 
with  cement.  The  steam  is  introduced  beneath  a  false 
bottom  of  wood,  perforated  with  numerous  holes.  The 
condensed  steam  escapes  through  an  opening  at  the 
basis  of  the  chamber. 

The  temperature  of  the  heap  should  be  maintained 
between  70°  and  80°,  and  care  should  be  taken  to  keep 
it  uniform,  for  the  joint  action  of  heat  and  moisture  may 
dissolve  the  gelatine  and  cause  the  hides  to  be  scarred 
with  pits.  The  process  is  completed  in  twenty-four 
hours,  and  the  hair  is  scraped  off  in  the  usual  manner. 
Ox-hides  weighing  from  eighty  to  one  hundred  pounds 
experience  a  loss  of  twenty-four  to  twenty-eight  pounds. 


CHAPTER  XXVII. 

DEPILATION  BY  CAUSTIC  SODA. 

M.  F.  Boudet,  for  a  substitute  to  lime  for  raising  and 
depilating  hides,  proposes  caustic  soda.  For  this  purpose 
the  liquid  is  prepared  by  decarbonating  a  very  dilute 
solution  of  soda  ash  with  a  sufficient  quantity  of  lime, 
allowing  repose,  and  decanting  the  clear  supernatant 
liquor  of  caustic  lye.  Hides  immersed  in  this  liquor  swell 
out  rapidly  and  considerably,  and  are  ready  to  scrape  in 
two  or  three  days.  Moreover  the  alkali  forming  soluble 


DEPUTATION  BY  SULPHURET  OF  CALCIUM  AND  SODA.  171 

salts  with  the  fatty  portions,  facilitates  the  cleansing, 
and  produces  a  smoother  grained  side  than  is  common. 
Hides  thus  prepared  imbibe  the  tan  liquor  more  rapidly 
than  those  which  have  been  treated  with  lime.  They 
undergo  the  entire  process  of  tanning  in  one-third  of 
the  time,  and  suffer  less  loss  than  those  prepared  by  the 
usual  method.  Forty-four  pounds  of  salsoda  dissolved 
in  one  hundred  and  thirty-two  gallons  of  water,  and 
mixed  with  thirty-three  pounds  of  slaked  lime,  suffice 
for  steeping  two  thousand  two  hundred  pounds  of  fresh 
hides. 


CHAPTER  XXVIII. 

DEPILATION  BY  SULPHURET  OF  CALCIUM  AND  SODA. 

Boudet,  in  trying  the  old  method  of  depilating  by 
means  of  a  paste  of  orpiment  and  caustic  lime,  observed 
that  the  arsenic  had  no  decided  influence  upon  the  hair, 
and  that  the  depilatory  action  was  due  to  sulphuret  of 
calcium  in  the  nascent  state,  formed  by  the  reaction  of 
lime  upon  the  orpiment  (sulphuret  of  arsenic).  He  re¬ 
placed  the  orpiment  by  sulphuret  of  calcium,  which, 
when  made  into  a  paste  with  lime,  acted  so  promptly 
that,  after  twenty-four  or  thirty-six  hours’  contact,  the 
skins  were  completely  depilated.  The  lime  alone  has 
no  depilating  effect,  and  the  sulphuret  of  sodium  only  a 
partial  action. 

This  mode  of  preparing  the  hide  is  said  to  render 
it  highly  susceptible  of  being  quickly  tanned.  Experi¬ 
ence  has  to  decide  its  influence  upon  leather.  Tanners 
are  opposed  to  this  method,  which,  it  is  said,  surcharges 
the  leather  with  an  amount  of  water  that  escapes  by 
evaporation  during  storing,  to  the  great  loss  of  the  dealer, 
but  we  do  not  think  that  this  objection  is  tenable. 

Messrs.  Abram  &  Coste  use  the  following  process: — 

Macerate  the  hides  for  three  days,  put  them  in  the 
vat,  raise  three  times,  and  then  for  each  skin  put 

Potash ........  2^  drms. 

Lime  .  .  .  .  .  .  .  .  5  oz. 

Orpiment . J  “ 


172 


TANNING. 


This  same  quantity  is  sufficient  for  three  little  goat  or 
sheep-skins.  For  twenty-five  hides  take 

Potash  .  .  .  .  .  .  .  1  lb. 

Lime  .......  2  lbs. 

Orpiment  .  .  .  .  .  .  2  oz. 

The  whole  is  dissolved  in  fifty  gallons  of  water. 

This  vat  is  much  less  commended  than  the  preceding, 
and  is  liable  to  numerous  objections,  and  the  principal 
is  the  danger  to  health  accompanying  its  manipulation. 

Boettger  has  proposed  to  depilate  all  kinds  of  hides 
with  the  hydrosulphate  of  lime,  in  paste,  which  is  pre¬ 
pared  as  we  shall  see  hereafter.  To  use  it,  the  skin  is 
put,  with  the  hair  up,  on  a  table,  when  the  hair  is 
slightly  impregnated  with  the  paste,  so  as  to  penetrate 
as  far  as  the  roots.  In  the  same  way  is  treated  a  second 
hide,  and  it  is  placed  on  the  other.  These  two  hides  are 
covered  with  a  board  loaded  with  stones.  Two  hours 
after  the  hair  is  transformed  into  a  kind  of  soap,  which 
is  easily  removed. 

Preparation  of  the  Uydrosulphate  of  Lime. — The  hy- 
drosulphuret  of  calcium,  or  hydrosulphate  of  lime,  is 
prepared  by  saturating  a  very  thick  milk  of  lime  with 
sulphuretted  hydrogen  gas.  The  necessary  apparatus 
is  shown  below : — 


Fig.  34. 


DEPILATION  BY  SULPHURET  OF  CALCIUM  AND  SODA.  173 


It  represents  a  leaden  generator,  of  cylindrical  form, 
thirty-six  inches  high  by  twenty-four  inches  in  diameter, 
supported  by  a  wooden  jacket.  This  vessel  has  a  mov¬ 
able  cover  of  cast  iron,  with  a  projecting  ledge,  through 
which  pass  the  bolts  c ,  c,  for  fastening  it  down.  In  this 
cover  there  are  three  openings,  as  -shown  in  Fig.  35. 
The  larger  one,  g ,  is  the  man-hole  for  the  admission  of 
the  sulphuret  of  iron  and  for  clean¬ 
ing  out.  Of  the  two  smaller,  the 
one,  d,  receives  the  stationary  fun¬ 
nel  tube,  d,  through  which  the 
dilute  sulphuric  acid  is  to  be  intro¬ 
duced.  The  side  hole,  A,  contains 
a  short  tube,  6,  with  a  screw  at  its 
upper  end  for  coupling  the  flexible 
exit  tube,  m  (made  of  vulcanized 
rubber),  which  is  to  convey  the 
generated  gas  into  the  lime  paste 
contained  in  the  closely  covered  receiver,  x.  A  pipe 
running  down  the  side  of  the  generator,  interiorly,  is 
for  the  coupling  of  the  steam  pipe  when  the  admission 
of  steam  is  necessary. 

The  protosulphuret  of  iron  rests  upon  the  bottom  of 
the  generator.  When  the  sulphuric  acid  and  water 
(one  vol.  of  the  former  to  three  or  four  of  the  latter) 
are  poured  in  through  the  funnel  tube,  d,  to  the  height 
indicated  in  the  figure,  chemical  action  immediately 
ensues.  The  water,  which  is  composed  of  oxygen  and 
hydrogen,  is  decomposed,  and  the  former  gas  goes  at 
once  to  the  iron,  which  is  deserted  simultaneously  by 
its  sulphur,  and  thus  becoming  an  oxybase  indulges  its 
affinity  for  the  sulphuric  acid  and  unites  with  it  to  form 
sulphate  of  iron.  The  hydrogen  unites  with  the  sulphur 
to  form  sulphuretted  hydrogen,  which  escapes  through 
the  tube,  m ,  leading  into  the  milk  lime  with  which  it 
combines  as  hydrosulphuret  of  calcium.  The  current 
of  gas  is  continued  until  the  lime  is  saturated.  When 
the  current  of  gas  slackens,  hasten  it  by  the  addition  of 
a  little  acid  and  water.  The  occasional  admission  of 
steam  facilitates  the  reaction.  When  the  paste  is  satu- 


Fig.  35. 


174 


TANNING. 


rated,  stop  the  connection  of  the  tubes  m  and  k,  and 
the  generator  is  emptied  hy  the  man-hole,  g ,  so  as  to  be 
ready  for  another  operation. 

The  receiving  vat  should  be  of  wood,  strongly  bound 
with  iron  hoops,  and  fitted  with  a  cover  and  appliances 
for  keeping  it  close  enough  to  confine  the  gas,  but  not 
so  tight  as  to  cause  an  explosion. 

The  paste  should  be  made  in  quantities  as  required, 
for  it  must  be  used  immediately,  as  the  action  of  the  air 
soon  converts  it  into  sulphate  of  lime. 


CHAPTER  XXIX. 

COOL  SWEATING  PROCESS. 

This  process,  much  used  in  New  York,  New  Hamp¬ 
shire  and  the  northern  part  of  Pennsylvania,  has  all  the 
advantages  of  the  older  processes.  It  gives  a  gain  in 
the  leather  of  70  to  80  per  cent.,  while  the  warm  sweat¬ 
ing  process  yields  much  less,  and  the  liming  only  30  to 
40  per  cent. 

The  process  is  described  as  follows  :*  “  A  vault  or  pit 
is  prepared  for  the  reception  of  the  hides  ;  it  should  be 
12  feet  long,  12  feet  deep,  and  10  feet  wide.  The  wall 
may  be  built  of  stone  or  of  a  planked  frame.  There 
should  be  one  alley  for  entrance  six  feet  long,  having  a 
door  at  each  end,  the  outer  one  made  double,  and  filled 
in  with  spent  tan,  to  prevent  the  communication  of  warm 
air  from  without.  A  ventiduct,  made  of  planks  ten  or 
twelve  inches  square  should  extend  from  the  centre  of 
the  bottom  of  the  vaults  three  or  four  rods  therefrom, 
and  placed  not  less  than  four  feet  below  the  surface  of 
the  ground.  This  serves  both  as  a  drain  for  discharging 
the  water  of  the  vault  and  to  admit  damp,  cool  air,  to 
supply  the  place  of  that  which  has  become  rarefied,  and 
thus  keep  up  a  current  through  the  ventilator  at  the  top. 
The  ridge  of  the  roof  may  be  level  with  the  ground ; 
and  on  the  ridge,  extending  its  whole  length,  set  up  two 


*  Journal  Frank.  Inst.,  1843. 


COOL  SWEATING  PROCESS. 


175 


planks  edgewise,  two  inches  apart.  The  space  between 
these  is  to  be  left  open,  but  the  remainder  of  the  roof 
must  be  covered  with  earth,  to  the  depth  of  at  least  a 
yard.  The  earth  covering  upon  the  vault  and  drain  is 
to  preserve  a  low  temperature  for  the  hides  so  that  they 
may  unhair  without  tainting. 

“  Spring  water  should  be  conducted  either  in  pipes 
or  logs,  around  the  angles  formed  by  the  ceiling  with  the 
walls  of  the  vault,  from  which  water  should  be  allowed 
to  flow  in  small  quantities,  either  forming  a  spray,  or 
falling  so  as  to  raise  a  mist  or  vapor,  and  saturate  the 
atmosphere  of  the  vault.  The  temperature  of  spring 
water  is  generally  about  50°.  Water  evaporating  at  all 
temperatures,  it  is  plain  that  if  a  constant  supply  be 
afforded,  this  evaporation,  by  requiring  a  large  portion 
of  heat,  would  keep  the  temperature  of  the  vault  nearly 
uniform.  To  suspend  the  hides  in  the  pit,  place  three 
bars  lengthwise,  at  equal  distances,  near  the  ceiling 
with  iron  hooks,  two  or  three  inches  apart,  inserted 
therein.  Soak  the  hides  as  usual  for  breaking,  then 
hang  them  singly  upon  the  hooks  by  the  butt,  so  that 
they  may  be  spread  fully  open.  In  the  course  of  a  few 
days,  when  the  hair  begins  to  loosen  upon  the  upper 
parts,  take  them  down,  raise  the  middle  bar,  and  hang 
them  by  the  other  end  until  they  easily  unhair.  The 
hides  should  not  be  broken  until  they  are  taken  from 
the  vault  and  ready  to  unhair.  In  a  good  vault  where 
the  thermometer  ranges  from  40  to  56°,  which  it  should 
never  exceed,  and  where  there  is  a  free  circulation  of 
damp  air,  hides  require  from  6  to  12  days  for  unhairing. 
When  the  temperature  falls  below  44°  the  ventilator 
should  be  partially  closed,  and  when  it  rises  above  56° 
cold  damp  air  must  be  forced  in,  or  an  increased  quan¬ 
tity  of  cold  spring  water  may  be  thrown  from  a  hose.” 

Hides  thus  treated  are  free  from  all  extraneous  mat¬ 
ters,  and  contain  all  their  gelatin,  albumen,  and  fibrin, 
in  an  unimpaired  state.  “  The  action,”  says  the  author, 
“  is  confined  to  the  surface  or  grain  of  the  skin,  expand¬ 
ing  the  outer  portion,  softening  the  roots  of  the  hair,  and 
thus  rendering  its  removal  easy.  The  effect  is  due  to 


176 


TANNING. 


the  softening  action  of  the  vapor,  and  it  is  a  simple  case 
of  absorption  and  swelling  of  the  tissues  of  the  skin  and 
roots  of  the  hair.” 

This  process  has  been  proved  by  experience  to  obviate 
all  the  evils  arising  from  hot  sweating  or  from  unhairing 
the  hides  by  the  lime  process. 


CHAPTER  XXX. 

RAISING  BY  BARLEY  DRESSING. 

The  swelling  and  depilation  of  hides  by  this  process 
are  more  effective  and  rapid  than  -when  lime  is  used. 
Hides  treated  by  this  process  require  less  working  in  the 
water. 

This  process  requires  a  series  of  vats  varying  in 
strength.  The  hides  are  soaked  at  first  in  the  vat  con¬ 
taining  the  weakest  liquor,  then  pressed  and  washed. 

Mr.  Bouillerat,  of  Paris,  operates  as  follows:  The 
hides,  after  being  soaked  and  fleshed,  are  put  through 
the  dressings,  that  is,  are  subjected  to  the  action  of  barley 
water.  They  remain  three  days  in  the  first  or  dead  dress¬ 
ing,  as  much  longer  in  the  second,  when  they  are  freed 
from  the  hair,  and  placed  in  a  third  vat  in  which  they 
dilate,  swell  out,  and  acquire  consistence.  They  are 
taken  out  only  once  daily  from  the  dead  dressing,  and 
twice  from  the  others.  At  each  time  they  are  laid  in 
heaps,  and  there  left  during  an  interval  of  three  hours. 
After  these  three  dressings  the  hides  are  submitted  to  a 
fourth,  which  is  termed  the  new  dressing,  made  with 
145  lbs.  of  well-ground  barley  meal.  From  this  quan¬ 
tity  10  lbs.  are  taken  out  and  made  into  a  leaven  by 
being  kneaded  with  warm  water,  and  left  to  ferment 
from  12  to  14  hours,  in  which  time  it  sours  and  becomes 
sufficiently  ripe  for  the  operation.  In  summer  this 
leaven  is  thinned  out  with  tepid  water  in  sufficient  quan¬ 
tity  to  form  the  dressing;  in  winter  boiling  and  in  spring 
hot  water  is  used. 

From  the  new  dressing,  the  hides  are  passed  into  an- 


RAISING  BY  BARLEY  DRESSING. 


177 


other  similar  one,  and  allowed  to  remain  four  days  in  each. 
Eight  or  nine  hides  are  generally  worked  at  a  time. 

The  series  is  composed  of  four  or  five  vats.  The  first 
dressing  is  intended  to  wash  the  hides,  the  second  for 
depilation,  the  third  to  swell  them  and  impart  body,  and 
the  two  others,  which  are  new,  complete  the  action  of 
the  third.  These  preparations  are  termed  white  dress¬ 
ings,  and  require  five  weeks  in  summer  and  six  in  winter. 

After  having  gone  through  the  white  dressings,  the 
hides  are  carefully  washed,  and  placed  in  the  red  prepa¬ 
ration,  composed  of  225  lbs.  of  tan  well  mixed  with  2| 
hogsheads  of  water,  and  are  left  in  the  mixture  for  15 
days  in  summer  time,  and  one  month  in  winter.  During 
the  first  five  days  it  is  necessary  to  take  the  hides  out, 
once  daily;  to  be  sure  that  the  supply  of  bark  is  suffi¬ 
cient  when  the  skin  comes  from  the  preparation,  they 
are  to  be  washed  and  placed  in  the  vats.  Eight  or  nine 
skins  may  be  handled  at  one  working. 

At  Abbeville  (France)  tanners  have  adopted  the  follow¬ 
ing  method.  For  16  hides,  they  put  48  lbs.  of  barley 
meal  into  an  open-mouthed  tub,  and  mix  with  it  some 
sour  paste  made  of  flour  thinned  out  with  hot  water. 
They  add  to  this  mixture  \  a  lb.  of  yeast ;  fermentation 
soon  follows,  and  in  15  to  16  hours  the  leaven  is 
formed. 

This  leaven,  being  mixed  with  150  lbs.  of  meal  in  a 
tub  of  water,  forms  the  new  dressing  or  preparation. 

The  same  gradation  as  with  lime  is  observed  as  to 
these  dressings.  Before  the  hides  are  worked,  they 
should  be  cut  into  halves,  and  always  placed  with  the 
flesh  side  upwards. 

The  time  for  hides  remaining  in  the  dressing  is  as 
follows :  two  or  three  days  in  the  old  dressing,  five  or  six 
in  the  weak,  and  twelve  or  fifteen  in  the  third  and  fourth, 
which  are  the  strong  or  new  dressings.  Sometimes  the 
hides  are  sufficiently  raised  at  the  fourth  dressing,  and 
then  they  are  taken  out,  while  the  unfinished  ones  are 
put  into  a  fifth  dressing,  and  left  until  they  have  ac¬ 
quired  sufficient  swelling. 

During  summer  the  hides  are  drawn  out  twice,  and  in 
12 


178 


TANNING. 


winter  once,  and  left  to  drain  for  an  hour,  each  time, 
upon  a  trough  conveniently  situated  near  the  vat.  This 
operation  requires  about  six  weeks  in  summer  and  much 
longer  in  winter,  for  cold  retards  the  action. 

In  Sedan  they  use  nine  or  ten  small  vats,  each  of  about 
six  hogsheads  capacity.  There  is  a  regular  graduation  in 
the  strength ;  for  example,  after  the  first  operation  the 
second  becomes  the  first,  the  third  second,  etc.  Five 
hides  are  placed  in  the  first  vat,  where  they  remain 
from  24  to  28  hours ;  they  are  transferred  to  the  second, 
which  is  a  little  more  sour,  and  so  on  successively  through 
all  the  vats.  It  often  happens  that  the  hides  attain 
the  necessary  degree  of  dressing  at  the  fourth,  third,  etc. ; 
then  it  is  useless  to  treat  them  further.  These  sour 
liquors,  after  having  served  for  ten  operations,  still  re¬ 
main  acid,  and  can  be  used  again  according  to  their  de¬ 
gree  of  strength. 

After  the  skins  have  been  treated,  they  are  washed  in 
clear  water  for  the  removal  of  the  dirt,  and  when  they 
come  to  the  last  dressing  they  are  rinsed  and  scraped 
over  with  the  fleshing  knife ;  at  last  they  are  again  put 
in  water  and  brushed  over  on  the  hair  side. 

Some,  after  this  manipulation,  lay  the  hides  in  the 
vats,  but  the  greater  number  subject  them  at  first  to  a 
red  dressing.  This  dressing  is 
given  by  spreading  the  hides  in  a 
vat,  one  above  the  other,  and 
placing  between  each  pair  two  or 
three  handfuls  of  ground  bark. 
They  add  water  until  the  hides  are 
submerged.  This  process  requires 
two  days,  and  the  hides  require 
only  one  withdrawal  to  allow  them 
to  drain. 

In  giving  the  finishing  wetting,  care  must  be  observed 
to  supply  bark  where  it  is  wanted. 

This  method  of  cleaning  and  unhairing  presents  as 
many  objections  as  the  lime  process,  and  besides  has 
other  disadvantages.  The  efficiency  of  the  bath  is  de¬ 
stroyed  when  exposed  to  a  low  temperature,  and  it  is 


Fig.  36. 


RAISING  BY  BARLEY  DRESSING. 


179 


not  resorted  to  when  the  bath  thaws.  The  leather  is 
exposed  to  be  injured  by  the  putrid  fermentation  of  the 
materials. 

In  England,  for  coarse  hides,  they  have  used  for  a 
long  time  the  barley  dressing,  and  they  complete  the 
operation  in  six  days.  The  hides  pass  through  four  or 
five  dressings,  and  from  the  weak  progressively  to  the 
strong.  The  hides  remain  24  hours  in  the  last  vat, 
which  is  new,  and  has  been  soured  for  15  days.  It  is 
made  by  mixing  60  lbs.  of  barley  meal  in  hot  water. 
As  a  long  time  is  allowed  for  the  development  of  acid 
and  consequently  the  dressing  is  more  active  than  ordi¬ 
nary  ones,  it  becomes  necessary  to  watch  carefully  when 
the  required  point  is  reached,  otherwise  the  hides  will 
be  injured. 

Barrois  operates  differently.  He  works  five  series  of 
four  tubes  each,  at  a  time.  These  vats  are  3^  feet  high 
and  5  feet  in  diameter,  and  of  a  capacity  for  8  hides ; 
each  series  comprising  32  hides.  It  is  necessary  to 
take  out  all  the  hides  twice  daily  during  the  dressing. 
Every  four  days  a  new  preparation  is  made  up  in  one 
of  the  vats,  which  is  deposited  in  that,  the  dressing  of 
which  was  the  weakest  after  running  it  off  and  washing 
out  the  vat.  The  third  vat  then  becomes  the  last, 
and  that  which  was  the  first  and  strongest  becomes  the 
second. 

The  hides  remain  eight  days  in  the  fourth  or  weakest 
vat,  four  days  in  the  third,  which  then  becomes  the 
weakest ;  then  the  same  length  of  time  successively  in 
the  second  and  the  first,  after  remaining  six  days  in 
which  they  are  stripped  and  deposited  in  a  fresh  series. 
In  this  they  remain  four  days  in  a  dressing  which  has 
only  been  used  once,  four  days  more  in  another  similar 
one,  and  four  days  each  in  two  fresh  vats. 

Each  fresh  preparation  for  eight  hides  is  composed  of 
145  pounds  of  ground  barley,  and  the  leaven  is  made 
with  30  lbs.  of  the  above  barley  mixed  with  yeast  and 
hot  water. 

This  interval  of  thirty-two  days  is  sufficient  for  the 
requisite  preparation  of  the  hides,  either  in  summer  or 


180 


TANNING. 


winter ;  but  in  the  latter  season,  hot  water  is  generally 
used  in  the  proportion  of  five  to  six  buckets  to  each 
preparation  in  order  to  hasten  the  fermentation. 

A  hide  dressed  by  this  process  weighing  100  lbs. 
takes  about  200  lbs.  of  bark  as  follows :  25  lbs.  in  the 
red  dressing,  30  in  the  first  powder,  25  in  the  second, 
and  20  in  the  third.  The  preparation  is  maintained 
fresh  by  the  addition  of  a  few  pints  of  vinegar. 

When  the  hides  have  been  sufficiently  raised  in  the 
white  dressing,  they  are  put  in  the  red,  which  is  com¬ 
posed  of  clear  water  and  two  or  three  handfuls  of  bark 
placed  between  the  hides.  The  hides  remain  thus  three 
or  four  days,  when  they  are  again  treated  by  the  same 
quantity  of  bark  as  at  first,  and  left  three  days  longer ; 
after  that  time  they  are  ready  to  be  laid  in  the  vats  in 
the  same  manner  as  in  the  lime  process. 

This  process,  a  little  modified,  is  one  of  the  best  that 
can  be  followed.  A  fresh  vat  can  be  used  every  two 
days,  and  thus  there  will  be  a  gain  of  half  of  the  time. 
Instead  of  clear  water,  it  is  better  to  use  the  liquor  of 
the  tan  pits,  and  to  place  between  each  hide  a  layer  of 
coarsely  ground  bark  for  the  red  dressing. 

Two  hundred  pounds  of  bark  are  not  sufficient  for 
100  hides  averaging  200  pounds  each.  In  some  places 
they  use  300  pounds,  but  the  quantity  depends  much 
upon  the  quality  of  the  bark  and  the  fineness  of  the 
powder. 

The  following  is  a  very  good  method:  For  a  dressing 
for  eight  hides  averaging  50  lbs.  each,  from  100  to  140 
lbs.  of  barley  meal  must  be  employed.  Some  tanners 
use  all  the  meal  at  once,  but  others  again  make  a  leaven 
with  24  lbs.  of  the  meal,  which  they  do  not  mix  with 
the  rest  until  twelve  hours  have  elapsed.  Many  tanners 
keep  up  the  acidity  of  the  dressing  by  throwing  into 
each  one  three  or  four  bottles  of  vinegar,  at  different 
times. 

Other  tanners  put  the  whole  of  the  meal  in  the 
tub  and  drench  it  with  enough  tepid  water  to  form  a 
fermentable  paste,  and  leave  it  twenty-four  hours.  The 
dressing  is  made  by  adding  to  the  fermented  flour  warm 


RAISING  BY  BARLEY  DRESSING. 


181 


water  in  winter,  and  water  at  the  ordinary  temperature 
in  summer.  The  quantity  of  water  varies  according  to 
the  number  of  hides.  These  are 
divided  into  two  sides  before  sub¬ 
jecting  them  to  the  dressings,  in 
which  they  remain  three  weeks 
in  summer  and  four  in  winter. 

The  hides  are  taken  out  daily, 
and  placed  on  planks  across  the 
vat,  as  shown  in  the  figure,  and 
there  left  for  two  or  three  hours. 

The  vats  are  4J  feet  in  height  and 
as  great  in  diameter.  In  some  places  tanners  use  nine 
or  ten  vats,  but  three  are  sufficient ;  the  first  for  the 
dead ,  the  second  for  the  feeble ,  and  the  third  for  the 
new  preparation.  The  depilation  is  performed  as  soon 
as  the  hair  can  be  pulled  off  without  resistance. 

Scrape  the  hides  with  the  usual  precaution,  with  the 
round  knife,  and  throw  them  into  the  water,  where  they 
remain  about  two  hours.  Rinse,  draw  out,  and  place 
them  in  the  second  preparation.  Experience  alone  de¬ 
termines  the  length  of  time  necessary  for  the  weak  bath. 
While  they  are  attaining  the  requisite  body,  they  must 
be  taken  out  daily,  and  replaced  in  the  vats. 

If  the  hides  have  not  been  fleshed  before  the  dressings, 
it  is  necessary  to  subject  them  to  this  operation,  after 
drawing  them  from  the  weak  vat;  but  it  is  better  to  do 
it  previously.  After  the  fleshing,  soak  them  for  two 
hours  in  water,  rinse  carefully,  and  place  them  in  the 
new  dressing,  which  is  prepared  with  barley  meal,  in  the 
proportion  of  twelve  pounds  for  each  hide.  A  leaven  is 
made  with  one-fourth  of  this  quantity  of  meal,  and  when 
it  begins  to  ferment,  the  residue  is  added,  and  the  whole 
thoroughly  diffused  in  an  amount  of  water  proportional 
to  the  number  of  hides  to  be  worked. 

The  time  in  the  third  dressing  varies  according  to  the 
nature  of  the  hide,  the  season,  &c. 

The  hides  during  this,  as  in  other  dressings,  should 
be  daily  removed  from,  and  replaced  in  the  vats. 

The  hides  are  then  put  into  the  red  dressing,  made  of 


Fig.  37. 


182 


TANNING. 


liquors  from  the  tan  vats,  to  which  must  be  added  about 
6^  lbs.  of  coarse  bark  for  every  hide. 

You  must  be  careful,  in  this  operation,  to  avoid  delay, 
and  not  give  the  bark  time  to  settle  to  the  bottom  of 
the  vat,  for  the  skins  will  be  unequally  tanned. 

It  is  better  to  commence  work  with  the  red  dressing 
very  early  in  the  morning,  so  that  the  operation  may  be 
completed  before  night,  and  the  leaving  of  the  skins  too 
long  without  stirring  should  be  avoided.  This  way  the 
hides  may  be  taken  out  and  replaced  twice  daily,  once 
in  the  forenoon  and  once  in  the  afternoon.  The  first 
time  they  are  allowed  to  drain  ten  minutes,  and  then 
replaced.  The  second  time  they  are  drained  for  fifteen 
minutes,  and  in  the  interval  the  same  amount  of  bark  is 
added,  and  the  vat  thoroughly  stirred.  The  next  two 
days  the  hides  are  taken  out  and  put  back  three  times 
daily,  and  left  to  drip  half  an  hour  each  time.  Twenty- 
five  pounds  of  fresh  bark  are  added  in  the  morning,  and 
npon  every  removal  of  the  hides  the  dressing  is  carefully 
stirred.  No  bark  is  added  on  the  fourth  day,  and  the 
hides  are  taken  out  only  twice,  and  are  allowed  to  drain 
three-fourths  of  an  hour  each  time. 

The  last  step,  upon  the  fifth  day,  requires  a  new  mani¬ 
pulation.  After  the  hides  have  been  taken  out  in  the 
morning,  and  drained  three-fourths  of  an  hour,  two 
workmen  stir  up  the  contents  of  the  vat,  while  two 
others  put  back  the  hides,  flesh  side  down,  care  being 
taken  to  spread  some  handfuls  of  bark  upon  each.  When 
the  vat  is  full,  the  last  skin  is  put  in  with  the  hair  side 
down,  and  some  bark  is  sprinkled  over  it.  After  ten 
days  take  the  hides  out,  rinse  them  in  water  used  for 
dressing,  and  lay  them  in  the  vats. 

The  red  dressing  is  a  very  important  step  in  the  pro¬ 
cess  of  tanning.  It  gives  firmness  to  the  hide,  by  an 
incipient  tanning,  which  serves  as  preliminary  to  that 
which  is  to  follow.  A  skin  which  has  not  received  a  red 
dressing  is  tanned  so  rapidly  that  it  shrinks,  becomes 
hard,  wrinkled,  and  insusceptible  of  perfect  combination 
with  the  tannin.  The  feeding  of  the  vat,  according  to 
Dessables,  can  never  be  too  strong,  for  the  hide  neither 


WALLACHIA  LEATHER. 


183 


hardens  nor  shrinks  in  the  powder.  However,  we  be¬ 
lieve  that  a  strong  feeding  of  a  vat  is  injurious.  Experi¬ 
ence  has  proved  that  with  a  hide  directly  in  contact  with 
a  concentrated  liquor  of  bark,  the  tanning  is  very  active, 
but  the  combination  of  the  tannin  with  the  gelatine  is 
so  rapid  upon  the  exterior  surfaces  that  the  interior  is 
unacted  upon,  as  is  the  case  in  hasty  tanning. 

There  are  some  tanners  who  contend  that  barley- 
dressed  hides  require  about  twenty  per  cent,  more  bark 
than  those  which  have  been  limed.  In  many  places 
they  take  for  a  barley-dressed  hide  averaging  100  lbs.  in 
weight  225  lbs.  of  bark,  as  follows:  84  for  the  first,  75 
for  the  second,  and  66  for  the  third.  The  same  results 
can  be  obtained  with  rye  flour. 

We  do  not  recommend  these  processes  to  manufac¬ 
turers;  their  use  is  now  abandoned  in  consequence  of 
the  uncertainty  of  their  action.  We  shall  speak  now  of 
Wallachia  leather,  which  is  similar  to  this  process. 


CHAPTER  XXXI. 

WALLACHIA  LEATHER. 

This  kind  of  leather  is  manufactured  in  Wallachia, 
and  is  made  by  barley-dressing,  in  a  single  vat.  The 
hides  are  softened  in  water,  and  trampled  under  foot, 
then  worked  on  the  flesh  side  with  the  scraping  knife  to 
render  them  supple ;  at  last  they  are  rinsed  in  water  and 
hung  up  to  drain.  They  examine  then  if  the  hair  can 
be  easily  detached,  for,  in  warm  climates,  in  summer, 
this  is  effected  without  any  other  preparation.  If  fresh 
skins  are  used,  they  are  left  to  ferment  so  as  to  remove 
the  hair,  and,  after  removing  the  tail,  horns,  and  ears, 
the  skins  are  salted  without  being  soaked. 

The  salting  consists  in  sprinkling  over  each  large  hide 
from  four  to  six  pounds  of  salt,  alum,  and  saltpetre, 
doubling  it  on  the  centre,  so  that  one  half  is  folded  over 
the  other,  stacking  it,  and  covering  the  pile  with  straw. 
The  hides  soon  become  heated,  and  it  is  then  necessary 
to  turn  them  once  or  twice  daily,  and  change  the  folds, 


184 


TANNING. 


and  the  sides,  so  as  to  insure  a  uniform  fermentation. 
When  the  hair  can  be  detached  readily,  the  depilation 
is  immediately  commenced,  for  any  delays  are  injurious 
to  the  grain  of  the  leather.  If  they  cannot  be  depilated 
immediately,  soak  them  in  water  for  one  or  two  days, 
but  no  longer,  for  fear  of  their  undergoing  an  incipient 
fermentation. 

Salt  is  not  necessary,  as  we  have  said  above ;  as  a 
general  rule  the  hair  should  give  with  a  noise,  when  it 
is  plucked  out  with  the  fingers,  and  the  more  difficult 
the  depilation  the  better  the  skin,  as  it  is  a  proof  that 
it  has  suffered  no  alteration.  The  parts  denuded  during 
or  previous  to  the  operation  should  be  moistened  with  a 
solution  of  salt,  so  that  they  may  not  be  overheated  be¬ 
fore  the  other  portions  are  ready  for  the  depilation. 

The  depilation  can  also  be  effected  with  the  help  of 
stable  manure.  The  three  methods  by  fermentation  are 
the  most  objectionable,  as  the  skins  nearly  always  suffer 
more  or  less  from  incipient  putrefaction.  In  the  follow¬ 
ing  method  it  is  better  to  employ  the  exhausted  vats. 
As  soon  as  the  depilation  is  finished,  the  raising  is 
effected  in  the  following  manner: — 

For  seven  hides,  each  averaging  eighty  pounds,  take 
twenty  pounds  of  wheat  flour  that  you  make  into  a 
leaven,  diffuse  in  water  to  a  pasty  consistence,  and,  to 
accelerate  the  fermentation,  add  a  gill  and  a  half  of  vine¬ 
gar.  This  leaven  requires  twenty-four  hours  to  be  made, 
after  which  it  must  be  kept  covered  in  a  warm  place  for 
three  or  four  days. 

The  tub  for  six  or  seven  hides  should  be  five  and  a 
quarter  feet  in  diameter,  and  three  and  a  quarter  feet  in 
height,  and  well  cleansed.  Fill  it  with  water  and  with¬ 
draw  from  it  six  or  seven  bucketsful,  boil,  and  use  a  part 
for  making  a  uniform  paste  out  of  ground  barley,  which 
afterwards  thin  out  with  cold  water  till  of  a  syrupy  con¬ 
sistence.  This  paste  is  boiled  till  it  froths,  constantly 
stirring  with  a  wooden  paddle,  and  when  it  has  bubbled 
or  foamed  three  times,  it  is  to  be  poured  into  the  tub 
destined  for  the  dressing,  and  cooled  by  stirring  with 
the  paddle  kept  moving  constantly  in  the  same  direction. 


WALLACHIA  LEATHER. 


185 


The  temperature  should  be  such  that  the  hand  can  be 
kept  in  it.  Then  stir  in  six  pounds  of  salt,  cover  the 
tub,  and  leave  it  two  weeks  to  sour.  However,  the  mix¬ 
ture  is  stirred  twice  daily,  and,  in  order  to  confine  the 
heat,  the  cover  should  not  be  kept  off  longer  than  is 
necessary. 

Take  the  skins  from  the  rinse-water,  strung  in  threes 
upon  a  rope  thrown  into  the  tub,  and  leave  for  four  or 
five  days.  Each  day  withdraw  them  twice,  rinse,  leave 
to  drain  a  minute,  and  put  back  in  the  tub.  When  the 
skins  are  well  broken,  and  the  hair  side  has  become  suf¬ 
ficiently  soft  to  retain  the  impression  of  the  finger-nail, 
they  are  taken  out  and  fleshed.  If  some  portions  of  the 
hair  should  still  adhere,  spread 
the  hides  upon  the  beam,  and  Fig.  38. 

scrape  them  with  the  knife  rep¬ 
resented  in  Fig.  38.  When 
shaved,  rinse  in  clean  water, 

suspend  and  leave  to  drain  twenty-four  hours.  In  the 
mean  time  make  and  ferment  in  the  same  way  a  second 
leaven  with  sixteen  pounds  of  meal. 

The  sour  liquor  is  then  transferred  from  the  vat  of  the 
first  dressing,  and  the  clear  supernatant  portion  poured 
into  the  second  tub  wherein  is  to  be  given  the  comple¬ 
ment,  which  is  nothing  more  than  a  repetition  of  the  pre¬ 
ceding  operation.  Six  or  seven  bucketsful  of  the  clear 
sour  water  of  the  tub  are  taken  from  each  vat,  are  boiled, 
and  a  portion  stirred  up  with  about  fifty  pounds  of  ground 
barley,  or  about  eight  pounds  for  each  hide.  Add  gradu¬ 
ally  the  residue  of  the  hot  water,  boil  gently,  and  dis¬ 
tribute  in  the  new  dressings,  stir,  take  out  a  bucket  or 
two,  and  heat  it  nearly  to  ebullition.  The  second  leaven, 
made  with  eight  pounds  of  meal  is  distributed  in  the 
tubs;  add  to  each  four  or  six  pounds  of  salt  and  stir 
well.  Take  out  several  bucketsful  and  hold  them  in  re¬ 
serve,  so  as  to  have  them  ready  for  supplying  any  defi¬ 
ciency  in  the  quantity  of  the  liquid,  which  should  not 
be  greater  than  eight  inches  in  height.  If  this  method 
is  too  tedious,  it  may  be  simplified  by  making  one  step 
of  the  two,  and  using  at  once  thirty  pounds  of  leaven, 


186 


TANNING. 


one  hundred  and  twenty  of  barley,  and  ten  of  salt,  for 
each  dressing  of  six  hides. 

By  the  ordinary  process,  tanners  use  at  one  time  in 
their  first  new  dressing,  just  twice  the  quantity  of  barley 
that  would  be  employed  here,  and  when  their  first  new 
dressing  is  not  sufficient,  they  make  a  second,  which 
renders  the  process  more  tedious  and  costly  than  that  of 
Wallachia.  It  is  also  necessary  to  say  that,  on  the  ad¬ 
dition  of  salt,  the  dressing  must  always  be  well  stirred, 
and  two  or  three  bucketsful  of  the  liquor  drawn  out  from 
each,  and  kept  warm,  to  be  poured  into  the  vat  in  order 
to  maintain  the  temperature.  Several  other  bucketsful 
are  poured  into  a  reserved  tub,  so  that  no  more  liquor 
may  remain  in  each  dressing  than  is  sufficient  to  cover 
the  skins  subjected  to  its  action.  Some  tanners  think 
it  better  to  make  the  whole  of  the  composition  at  once, 
for  it  may  so  happen  that  the  complement  made  with 
the  new  quantity  of  barley  may  retard  the  progress  of 
fermentation,  and  that  the  liquor  must  then  be  heated 
to  a  temperature  that  would  be  injurious  to  the  skins. 

The  single  composition  is  made  in  different  ways:  1. 
From  barley  or  rye  meal,  without  leaven,  prepared  over 
night  with  boiling  water.  2.  From  equal  parts  of  bar¬ 
ley  meal  and  leaven,  thinned  out  with  water  and  heated 
nearly  to  ebullition  just  previous  to  putting  in  the  skins. 

3.  From  wheat  bran. in  the  proportion  of  a  half  bushel 
per  hide,  thinned  out  with  hot  water,  and  after  a  day’s 
fermentation  mixed  with  one  pound  of  salt  for  each  hide. 

4.  From  leaven  of  barley  or  rye  as  substitute  for  that 
from  wheat  in  the  proportion  of  6  to  8  lbs.  of  flour  per 
hide.  When  the  leaven  rises,  thin  it  out  with  water  at 
86°,  and  add  the  salt  just  before  the  skins  are  put  in. 

Method  of  Working  the  Dressings. — When  the 
fermentation  is  well  established,  the  dressings  are  ready 
to  receive  the  skins ;  then  take  them  from  the  hangers, 
and  pass  them  in  and  out  of  the  liquor  several  times 
to  gradually  equalize  the  temperature.  Leave  them 
a  few  minutes,  on  the  cover  of  the  tub,  to  drain.  Stir 
the  liquor  and  put  back  the  skins,  cover  the  vats,  and 
maintain  the  heat  of  the  dressings  with  the  liquor 


WALLACHIA  LEATHER. 


187 


kept  warm  and  in  reserve.  Fifteen  minutes  after  take 
out  the  hides,  let  them  drain  fifteen  minutes,  and  put 
them  back.  Half  an  hour  after  remove  them,  let  them 
drain  a  quarter  of  an  hour,  return  them  to  the  vat,  and 
take  them  out  again  to  drain  twenty  minutes.  At  last 
they  are  taken  out  after  two  hours,  and  the  same  round 
is  repeated  a  seventh  and  eighth  time  after  a  similar 
interval.  The  liquor  must  be  stirred  every  time  so  as 
to  cause  the  meal  to  rise  from  the  bottom.  Be  careful 
to  cover  the  vats  immediately  after  putting  in  the  hides. 
The  heat  of  the  vats  should  be  maintained  at  from  105° 
to  120°  F.,  by  additions  of  reserved  liquor  kept  warm. 

Two  workmen  place  the  hides  in  the  vats ;  they  take 
them  by  the  opposite  ends,  spread  them  out  upon  the 
flesh  sides,  and  then  push  them  down  with  a  pole. 

The  action  of  the  white  dressing  is  completed  in 
thirty-six  hours;  the  acetic  fermentation  so  expands  the 
hides  that  they  become  as  thick  as-leather  into  which 
they  are  about  to  be  converted.  Care  must  be  taken 
not  to  leave  them  in  the  liquor  after  this  point  has  been 
attained,  for  it  injures  the  leather.  The  same  result 
occurs  if  the  liquor  is  too  strong. 

When  the  skins  have  been  removed  from  the  liquor, 
the  clear  portion  is  reserved  for  a  new  dressing,  for 
which  purpose  it  must  be  treated  with  a  complement 
stronger  than  the  first.  This  acid  liquor  facilitates  the 
fermentation  of  the  new  composition,  which  sours  ra¬ 
pidly.  In  this  manner  the  white  dressings  are  in  train, 
and  may  be  kept  at  one-half  the  expense  of  flour,  time, 
and  money. 

After  the  hides  are  taken  out  of  the  dressings,  they 
are  left  to  drain  on  the  cover;  and,  when  cooled,  they 
are  soaked  in  water  a  few  moments;  in  order  to  effect 
the  removal  of  a  viscous  coating  derived  from  the  barley, 
they  are  drained  anew. 

Now  they  are  submitted  to  the  red  dressing,  which 
prepares  them  for  the  tanning.  To  prepare  this  dress¬ 
ing,  charge  the  tub  with  about  forty  pounds  of  crushed 
bark,  which  is  mixed  in  water,  then  place  the  hides  in 
this  mixture.  Take  them  out  at  noon,  allow  them  to 


188 


TANNING. 


drain  seven  or  eight  minutes,  and  again  in  the  evening 
for  a  quarter  of  an  hour.  Before  putting  them  back  the 
last  time,  treat  the  liquor  with  forty  pounds  of  crushed 
bark,  thoroughly  stirred.  The  mornings  of  the  second 
and  third  days,  add  twenty-four  pounds  of  bark,  take  out 
the  hides  daily,  and  every  time  drain  for  half  an  hour. 
The  fourth  day  take  them  out  only  twice,  morning  and 
evening;  add  no  bark,  and  allow  forty- five  minutes  to 
drain.  The  fifth  day  take  out  the  hides  in  the  morning, 
drain,  and  stir  the  liquor  thoroughly;  return  the  hides 
to  the  tub,  hair  side  uppermost.  Throw  some  handfuls 
of  bark  between  each  skin,  and  on  the  top  of  the  last 
one,  which  should  have  its  flesh  side  uppermost.  Leave 
the  hides  eight  or  ten  days,  remove,  rinse,  and  put  them 
into  the  vats. 

Bran  Dressing. — According  to  some  tanners,  the  red 
dressings  may  be  omitted  if  the  white  dressings  are  made 
with  bran,  hut  the  opinion  of  the  majority  of  tanners  is 
in  favor  of  red  dressing.  However,  we  shall  say  a  few 
words  about  the  method  employed. 

The  bran  dressings  are  made  either  cold  or  hot.  For 
the  first,  a  leaven  is  prepared  with  yeast,  or  made  with 
one  and  a  half  pound  of  wheat  or  rye  flower,  for  each 
hide,  and  kept  at  a  moderate  temperature.  The  skins 
are  freed  from  all  adhering  dirt  which  soils  them;  they 
are  then  fleshed  and  dipped.  Boil  a  quantity  of  water, 
sufficient  for  a  bath  for  all  the  skins,  with  bran,  seven 
or  eight  pounds  for  each  skin.  Cover  the  boiler,  and 
when  the  liquor  has  sufficiently  fermented,  pour  it  into 
a  vat  in  which  the  skins,  previously  rinsed,  have  been 
deposited. 

While  the  skins  are  getting  warm,  heat  another  quan¬ 
tity  of  water  till  it  simmers,  and  mix  it  with  the  ferment 
made  at  the  beginning  of  the  operation.  Take  the  skins 
out  of  the  bath,  pour  the  fresh  mixture  into  the  vat, 
mix  with  it  salt  in  the  proportion  of  a  little  more  than 
a  pound  for  each  skin,  stir,  and  deposit  the  hides  in  it. 
Six  hours  after  withdrawing  the  skins  replace  them, 
after  a  portion  of  the  liquid  has  been  previously  taken 
out,  heated,  and  well  mixed  with  the  contents  of  the  vat. 


WALLACHIA  LEATHER. 


189 


Repeat  this  operation  every  six  hours  during  the  two 
succeeding  days.  As  soon  as  the  hair  is  ready  to  come 
off,  remove  it  from  the  surface ;  then  the  skins  are 
passed  over  lightly  upon  the  flesh,  soak  them  in  cold 
water  for  a  quarter  of  an  hour,  replace  them  in  the  vat, 
and  leave  them  until  sufficiently  raised,  being  careful  to 
keep  the  vat  perfectly  covered  so  as  to  retain  the  heat. 
The  raising  is  generally  completed  at  the  end  of  three 
days,  if  a  portion  of  the  liquor  in  the  vat  has  been  re¬ 
heated  from  time  to  time. 

Rinse  the  skins,  and  let  them  soak  for  some  hours  in 
fresh  water.  Remove  the  hair  where  it  is  ready  to  be 
detached,  rinse  the  skins,  pass  lightly  over  the  flesh 
side,  soak  some  hours  in  water,  and  deposit  them  again 
in  the  vat  in  order  to  raise  them. 

This  method  is  very  convenient  for  tanners  who 
manufacture  on  a  small  scale,  as  it  is  inexpensive. 

Decomposition  of  the  White  Dressings.— These  dress¬ 
ings  are  sour  pastes  of  barley,  rye,  or  wheat,  which,  under 
certain  circumstances,  undergo  a  decomposition,  and  it 
is  believed  that  lightning  produces  this  effect.  Some 
tanners  place  in  the  vat  scraps  of  old  iron  enveloped  in 
linen  rags  upon  the  approach  of  a  thunder-storm  ;  while 
others  dissolve  from  one-half  to  one  pound  of  sal  ammo¬ 
niac  in  the  vats,  under  the  belief  that  these  substances 
prevent  the  injurious  consequences  of  the  turning  of  the 
liquors.  When  the  dressings  experience  this  kind  of 
decomposition,  they  are  unfit  for  any  further  use,  and 
render  the  skin  so  soft  and  spongy  that  the  quality  of  the 
leather  would  be  impaired. 

The  long  continuance  of  the  heat  of  the  summer 
causes  this  decomposition,  and  the  quality  of  the  dress¬ 
ings  is  more  likely  to  be  injured  in  the  three  summer 
months  than  in  all  the  rest  of  the  year. 

Cold  has  no  influence  upon  them,  it  only  diminishes 
their  efficacy ;  and  the  skins  may  be  allowed  to  remain 
in  them  even  when  the  surface  is  frozen,  if  afterwards 
they  are  replaced  in  fresh  dressings. 


190 


TANNING. 


CHAPTER  XXXII. 

EYE  DRESSING,  OR  TRANSYLVANIA  LEATHER. 

The  Transylvanians  work  their  hides  about  the  same 
way  as  Wallachians.  Their  method  differs  only  in  this, 
the  latter  use  20  lbs.  of  barley  while  the  former  use  only 
15  lbs.  of  rye,  which  they  divide  into  two  portions.  It 
enters  10  lbs.  in  the  first  composition,  and  eight  in  the 
second.  As  the  grounds  of  rye  keep  their  strength  and 
quality  longer  than  those  of  barley,  on  account  of  the 
gluten  they  contain,  they  are  not  thrown  away,  but  are 
used  even  after  decantation  of  the  sour  liquor,  which 
renders  this  process  less  costly  than  the  other. 

We  have  given  the  above  processes  to  satisfy  manu¬ 
facturers,  rather  than  to  induce  them  to  use  them ; 
for  the  dressings  with  barley,  and  generally  with  grains, 
are  not  followed  now,  on  account  of  the  influence  of  the 
temperature  on  them.  The  process  described  in  the 
following  Chapter  is  the  most  used  now. 


CHAPTER  XXXIII. 

RAISING  BY  SOUR  TAN  LIQUOR. 

This  method  was  first  practised  in  Germany,  but  has 
since  been  adopted  in  many  parts  of  France. 

This  process  is  the  most  difficult,  but  is  very  advan¬ 
tageous,  as  it  is  the  beginning  of  the  main  tanning  ope¬ 
rations,  and  serves  to  abridge  the  time  occupied  by  them, 
and  the  leather  prepared  by  it  is  of  much  superior  quality 
to  that  treated  by  lime,  barley,  or  rye.  We  shall  describe 
this  process  minutely  and  fully,  commencing  with  the 
account  of  those  originally  employed. 

The  first  is  by  Champion.  When  this  method  was 
first  employed  in  Prance  the  depilation  was  effected  by 
the  action  of  heat;  and  to  prevent  the  putrefaction,  from 
one  pound  to  one  pound  and  a  half  of  salt  was  sprinkled 
over  one-half  of  the  surface  of  each  skin — the  other  half 


RAISING  BY  SOUR  TAN  LIQUOR. 


191 


being  turned  over  upon  it,  and  the  edges  brought  to¬ 
gether  so  as  to  prevent  the  escape  of  the  salt.  From 
fifteen  to  twenty  hides  were  salted  in  this  manner,  and 
placed  one  above  the  other,  being  left  thus  four  or  five 
hours  in  spring  and  autumn,  and  seven  or  eight  in 
winter.  At  the  end  of  this  time  the  skins  were  folded 
again  in  the  opposite  direction,  the  bellies  being  placed 
upon  the  backs,  and  the  heads  under  the  tails,  the  whole 
being  piled  upon  one  another  so  as  to  be  exposed  equally 
to  heat.  The  skins  were  first  dried  with  the  hair  on, 
and  were  then  soaked  for  eight  days  in  running  water, 
beaten  with  the  feet  or  the  mace,  and  again  soaked  dur¬ 
ing  four  to  five  days.  They  were  beaten  a  second  time, 
rinsed  and  drained  upon  the  horse,  after  which  they 
were  salted  as  before  described.  After  being  freed  from 
acid  by  the  influence  of  heat,  to  which  they  were  ex¬ 
posed  in  a  tight  vaulted  apartment,  they  were  soaked  in 
running  water.  Then  the  skins  were  subjected  to  the 
steeping  in  sour  tan  liquor,  which  softens  and  enlarges 
the  fibres,  opens  the  pores,  and  raises  them  to  receive 
the  first  tanning. 

Another  method  was  to  deprive  the  skins  of  hair  by 
stacking  them  on  heaps,  as  represented  below,  and  pro¬ 
moting  warmth  by  covering  them 
with  straw  or  manure,  until  the  Fig.  39. 

hair  is  ready  to  be  removed.  If  it 
comes  off  with  difficulty  upon  the 
horse,  its  separation  is  facilitated 
by  the  use  of  sand  spread  upon  the 
hair  side.  This  method  is  disadvan¬ 
tageous,  and  injurious  to  the  skins. 

To  prepare  the  tan  liquor  for  the  bath,  the  bark  which 
has  been  used  for  the  second  or  third  set  of  vats,  in  the 
tan-yard,  is  deposited  in  a  vat  thus  arranged  that  the 
liquor  percolating  through  it  may  be  received  in  a  drain¬ 
ing-well  or  vessel  placed  under  it;  from  which  it  can  be 
returned  into  the  main  receptacle  again  and  again,  so 
as  to  secure  an  increase  of  strength  by  repeated  filtra- 
tions  and  solutions.  This  liquor  has  a  clear  red  color, 
an  acid  taste  like  that  of  good  vinegar,  and  from  this 


192 


TANNING. 


solution  a  number  of  baths  can  be  made  of  different 
strengths.  A  series  of  eight  baths  may  be  made,  the 
first  one  containing  one  part  of  the  liquor  and  seven  of 
water,  and  so  until  the  full  strength  is  attained.  When 
the  skins  are  freed  from  hair,  washed  and  fleshed,  they 
are  soaked  two  days  in  clear  water,  in  summer,  and  four 
or  five  in  winter,  being  careful  to  change  the  water 
every  day,  and  to  let  the  skins  drain  for  three  hours. 
When  the  skins  are  ready  for  raising ,  upon  being 
steeped,  they  are  deposited  in  vats  containing  the  in¬ 
fusion  of  spent  tan,  being  first  placed  into  the  weakest. 
While  remaining  in  these,  they  are  taken  out  every 
morning  and  evening,  and  allowed  to  drain  over  the  vats 
during  three  hours.  Towards  the  end  of  the  proceeding, 
when  in  stronger  infusions,  a  removal  of  the  vats  once 
a  day  is  sufficient. 

The  English  tanners  use  baths  with  less  acid  than 
those  employed  in  France;  they  are  infusions  of  fresh 
bark  in  water.  They  use  a  large  number  of  baths,  in¬ 
creasing  gradually  in  strength,  and  with  vats  of  sufficient 
capacity  for  fifteen  or  twenty  skins. 

From  all  the  methods  primitively  used  in  France,  the 
best  is  that  followed  at  St.  Germain,  and  thus  described 
by  Felalande :  They  generally  employ  twelve  infusions, 
the  two  last  being  new,  and  the  ten  first  consisting  of 
old  infusions  of  tan.  Each  bath  is  prepared  for  twelve 
skins. 

The  skins  having  been  scraped  and  washed,  are  de¬ 
posited  in  the  first  infusions,  the  weakest  of  all.  It  is 
necessary  to  have  the  bath  a  little  acid.  Twenty-four 
hours  after,  raise  the  twelve  skins,  let  them  drain  half 
an  hour,  and  introduce  them  into  a  stronger  infusion; 
throw  away  the  water  of  the  above,  which,  having  been 
used  ten  times,  has  no  more  strength. 

The  second  infusion,  while  a  little  stronger,  has  no 
sensible  acid  action  on  the  tongue ;  the  third  has  a 
little  more  strength,  and  so  forth.  Every  morning  raise 
the  twelve  skins  from  one  infusion  to  put  them  into 
another,  until  they  have  been  treated  in  the  ten  vats. 
When  taken  out  from  the  tenth  infusion  the  skins  are 


RAISING  BY  SOUR  TAN  LIQUOR. 


193 


put  into  the  first  new  infusion.  The  first  infusion  is 
composed  of  a  sour  water  in  which  20  lbs.  of  coarse  tan 
are  added  for  every  skin.  The  skins  stay  ten  days  in 
this  first  infusion.  At  last  the  skins  pass  from  this 
first  infusion  into  another  of  the  same  nature,  to  which 
you  add  20  lbs.  of  coarse  tan  for  every  skin.  The 
skins  stay  ten  days  in  this  infusion,  and  then  are  ready 
to  be  tanned.  An  elevated  temperature  is  injurious  in 
the  weakest  infusions,  and  when  the  operation  is  con¬ 
ducted  in  summer,  be  careful  to  not  let  the  temperature 
raise  too  high. 

The  sour  liquor  was  prepared  in  the  following  man¬ 
ner;  five  ordinary  vats  being  made  use  of: — 

The  first,  or  No.  1,  being  destined  for  the  weakest, 
and  the  last,  or  No.  5,  for  the  strongest  infusions. 

The  spent  tan  from  the  pit  in  which  skins  had  been 
imbedded  for  the  third  time  was  deposited  in  No. 
5,  and  warm  water  poured  upon  it  through  a  pipe  or 
spout.  The  water  filtering  through  the  tan  passed  into 
a  draining  well,  and  was  pumped  out  after  four  or  five 
days,  constituting  an  amount  of  tan  liquor  sufficient  for 
four  of  the  ordinary  weak  vats. 

The  pit  was  again  -filled  with  water,  which  after 
becoming  tan-liquor  was  transferred  into  the  vats  Nos. 
1  and  2,  and  the  contents  of  Nos.  3  and  4  were  com¬ 
posed  of  the  liquors  of  Nos.  1  and  2;  again  it  is  passed 
through  No.  5,  and  the  infusion  originally  drawn  from 
No.  5  was  replaced  in  it.  The  11th  and  12th  vats,  ori¬ 
ginally  referred  to,  were  made  up  from  the  contents  of 
No.  5,  and  the  other  ten  from  the  contents  of  Nos.  3 
and  4  diluted  in  the  proper  manner  with  those  of  Nos. 
1  and  2. 

The  best  tanners  in  France  use  now  the  following 
process  : — 

The  skins  are  carefully  fleshed  and  deprived  of  all 
superfluous  parts,  and  soaked  for  24  hours  in  fresh 
vtater.  When  perfectly  clean  and  well  rinsed,  they  are 
deposited  in  the  liquors  by  which  they  are  to ‘be  depi¬ 
lated  and  raised.  These  liquors  are  contained  in  a 
series  of  eight  or  ten  vats  made  of  oak,  hooped  with 
13 


194 


TANNING. 


iron  ;  they  are  3  feet  8  inches  in  depth,  and  5  feet  5 
inches  in  diameter.  In  each  vat  deposit  seven  or  eight 
skins,  and  cover  them  completely  with  the  liquor. 

Let  them  soak  24  hours  in  the  first  vat,  which  con¬ 
tains  the  weakest  liquor,  and  during  that  time  take 
them  out  twice  to  drain  one  hour,  being  placed  on 
boards  which  are  inclined  so  that  the  fluid  dripping 
from  them  runs  back  into  the  vat.  After  two  days, 
take  them  out,  let  them  drain  one  hour,  and  place  them 
in  the  second  vat,  which  contains  a  stronger  infusion. 
The  same  operations  are  repeated  daily  until  the  skins 
have  passed  through  all  the  vats.  If  at  the  end  of  this 
time  the  hair  appears  ready  to  fall  off,  it  is  removed 
from  the  skins  by  working  them  in  the  ordinary  manner 
upon  the  horse  with  the  round  knife.  In  cold  weather 
it  is  sometimes  the  case  that  the  process  has  not  been 
sufficiently  completed  at  the  end  of  the  time  mentioned, 
and  that  the  skins  require  exposure  to  the  strong  liquors 
for  five  or  ten  days  longer,  in  order  that  the  hair  may 
be  removed  with  facility. 

The  skins  thus  prepared  have  not  yet  been  raised 
sufficiently  to  be  tanned,  and  for  this  purpose  must  be 
exposed  to  the  influence  of  four  more  vats  of  tan-liquor 
gradually  increasing  in  strength.  The  mode  of  ope¬ 
rating  is  the  same  as  described  above.  After  having 
passed  through  these  four  vats,  they  are  deposited  in  a 
vat  of  the  size  before  mentioned,  nearly  full  of  strong 
fresh  tan  juice,  which  has  been  previously  thoroughly 
mixed  by  repeatedly  stirring  with  4  lbs.  6  oz,  of  sul¬ 
phuric  acid  of  66°.  During  the  first  day  of  their 
soaking,  the  skins  are  taken  out  twice,  and  left  to  drain 
two  hours ;  on  the  second  day  they  are  removed  twice, 
being  allowed  to  drain  the  same  length  of  time,  and  on 
the  morning  of  the  third  day  they  are  changed  to  the 
last  vast,  which  contains  the  strongest  tan-liquor  that 
can  be  procured,  previously  mixed  as  before  with  4  lbs. 
6  oz.  of  sulphuric  acid.  On  the  evening  take  out,  drain 
for  an  hour,  and  replace  in  the  vat.  The  next  day  and 
the  day  after,  take  out  again,  drain  the  same  length  of 
time,  and  deposit  again  in  the  liquor.  Three  hours 


RAISING  BY  SOUR  TAN-LIQUOR. 


195 


after  the  last  draining,  they  are  finally  removed  and  are 
ready  for  tanning.  In  cold  weather  the  skins  should 
be  kept  in  the  vats  two  days  instead  of  one.  The  flesh 
side  should  always  be  placed  upwards  in  the  vats. 

Preparation  of  the  Tan-Liquor.— The  tan-liquor  used 
in  the  processes  above  described  is  obtained  by  the 
filtration  of  water  through  the  partially  exhausted  bark 
of  the  second  and  third  series  of  vats  in  the  tanyard, 
and  derive  from  it  their  astringent  and  acid  properties. 
This  tan,  after  remaining  for  a  time  in  contact  with  the 
skins  in  the  vat,  loses  and  gives  up  to  them  the  greatest 
portion  of  its  tanning  ingredients,  and  then  is  readily 
disposed  to  ferment  or  acidify,  still  retaining  some  of 
its  tanning  properties,  but  becoming  more  and  more 
acid  as  these  are  removed  from  it  by  absorption  into  the 
tissues  of  the  skin.  These  qualities  are  calculated  to 
injure  the  leather  and  make  its  removal  from  the  vats 
necessary  before  it  has  been  too  long  exposed  to  the 
action  of  the  exhausted  and  acidified  tan. 

For  the  purpose  of  preparing  the  sour  liquor,  the  tan 
is  deposited  in  an  empty  vat  in  which  a  draining  well 
composed  of  oak  planks  has  been 
erected,  as  shown  in  the  following 
figure.  This  well  is  so  arranged  that 
the  fluid  can  only  enter  it  from  below, 
and  a  pump  adapted  to  it  serves  to 
withdraw  its  contents,  or  they  may 
be  removed  in  a  bucket.  The  vat  is 
then  filled  with  water,  and  the  solution 
formed  by  its  filtration  through  the 
tan,  is  raised  after  a  few  days  from  the 
well,  and  is  again  poured  over  the  surface.  This  pro¬ 
ceeding  is  repeated  over  and  over  again  until  the  tan  is 
entirely  exhausted  of  its  soluble  material.  The  top  of 
the  vat  is  kept  close  to  avoid  evaporation  of  the  fluid. 
In  place  of  this  method  the  tan  can  be  exhausted  in 
treating  of  tanning. extracts. 

From  fifteen  to  thirty  days  are  usually  required  to 
give  to  the  liquors  the  proper  degree  of  strength  and 
acidity. 


Fig.  40. 


196 


TANNING. 


This  operation  can  be  done  only  in  large  establish¬ 
ments  ;  however,  with  few  vats  only  it  is  easy  to  make 
tanning  juice  ;  the  following  is  the  best  method :  Put  the 
old  bark  into  two  vats  that  you  fill  with  water  after 
three  or  four  weeks  of  maceration,  make  in  the  middle 
of  the  vat  a  hole  large  enough  to  introduce  a  pail,  draw 
the  juice  and  pour  it  back  on  the  same  vat,  where  it 
stays  five  days  more,  repeat  the  same  operation  until  the 
juice  has  the  required  strength.  Pass  it  through  a  sieve 
to  have  it  clear. 

This  juice  being  withdrawn,  pour  some  new  water, 
leave  eight  days,  and  draw.  The  juice  is  weaker.  For 
the  depilation  and  swelling  three  vats  and  five  solutions 
are  sufficient.  The  first  solution  is  very  weak,  and  its 
strength  increases  progressively.  Proceed  as  follows: 
Make  a  new  solution,  composed  of  pure  water,  or  better, 
very  weak  juice,  in  which  you  put  four  baskets  of  tan. 
Introduce  the  skins,  beat  them,  raise  them  three  times 
a  day,  morning,  noon,  and, night,  and  every  time  leave 
them  to  drain  one-quarter  of  an  hour;  draw  off  the 
liquor. 

The  second  day,  put  the  skins  in  a  weak  solution 
composed  of  three-quarters  water  and  one-quarter  juice, 
with  six  baskets  of  tan,  raise  three  times 

Fig.  41.  during  the  day,  leave  to  drain  one-quarter 
of  an  hour  each  time,  and  throw  away  the 
liquor.  Introduce  the  skins  in  another 
solution  composed  of  one-half  juice,  one- 
half  water,  and  six  baskets  of  tan,  as 
shown  in  Figure  41.  Leave  two  days, 
raising  three  times  a  day,  being  careful  to 
let  drain  half  an  hour. 

The  fourth  solution,  formed  of  the  clear  juice  of  the 
above,  lasts  twenty-six  days.  The  first  day  introduce 
the  skins  in  the  morning,  and  for  six  skins  add  thirty- 
six  pounds  of  bark.  The  second  and  third,  add  in  the 
morning  twenty  pounds  of  the  same  bark;  During 
these  three  days,  raise  three  times  a  day,  leave  to  drain 
half  an  hour  every  time.  The  fourth  day  add  twenty 
pounds  of  bark,  and  raise  twice.  The  fifth,  raise,  leave 


WORKING  ON  THE  BEAM. 


197 


to  drain  half  an  hour,  stir,  add  forty  pounds  of  bark,  and 
leave  eight  or  nine  days  without  moving.  After  nine 
days  pass  in  the  last  solution  or  pure  juice,  raise  twice 
a  day  for  three  days,  add  twenty-one  pounds  of  bark  in 
the  morning.  The  fourth  day  raise,  leave  to  drain  three- 
quarters  of  an  hour,  and  put  the  skins  back,  being  care¬ 
ful  to  throw  between  each  four,  eight  pounds  of  bark. 
Leave  eight  days,  and  then  the  skins  are  ready  to  be 
tanned. 

This  process  can  be  used  by  small  tanners,  and  to 
terminate  the  swelling  you  can  put  sulphuric  acid  in  the 
two  last  solutions,  but  instead  of  eight  or  nine  days  leave 
the  skins  only  three  days. 


CHAPTER  XXXIV. 

RAISING  BY  YEAST. 

Yeast  has  the  property  of  raising  skins,  and  has 
been  used  for  this  purpose.  It  is  mixed  in  a  vat  with 
warm  water,  the  vat  is  covered,  and  fermentation  takes 
place.  When  this  is  fully  established,  a  quantity  of  salt 
is  thrown  in,  and  the  skins  are  deposited  in  the  vat,  the 
contents  of  which  are  then  treated  precisely  as  in  the 
case  of  barley  dressing.  The  operation  can  be  conducted 
in  the  cold,  but  is  much  more  rapid  and  successful  if  the 
temperature  of  the  liquor  be  kept  elevated. 


CHAPTER  XXX Y. 

WORKING  ON  THE  BEAM. 

After  the  skins  have  been  prepared  for  the  separation 
of  the  hair  upon  them  by  any  one  of  the  numerous  pro¬ 
cesses  which  have  been  described,  the  next  proceeding 
is  to  remove  it  entirely  by  working  them  upon  the  beam. 
For  this  purpose  the  workman  makes  a  kind  of  pad  of 
two  or  three  folded  skins,  which  he  places  upon  the 
horse,  and  over  which  the  skin  to  be  operated  upon  is 
laid  with  the  hair  side  up,  and  he  then  scrapes  the  sur- 


198 


TANNING. 


face  strongly  from  above  downwards  with  the  scraper. 
After  the  hair  is  completely  removed  the  skin  is  washed 
or  soaked  in  a  trough  or  vat  full  of  water,  and  is  sub¬ 
jected  to  the  following  operations: — 

1.  The  flesh  and  other  parts  not  properly  belonging 
to  the  skin  are  removed  with  a  sharp  knife  called  the 
flesher ,  and  the  skin  is  again  washed  and  soaked  in  fresh 
water. 

2.  The  projecting  filaments  or  shreds,  and  those  parts 
of  the  borders  of  the  skin  which  are  thicker  than  the 
rest,  are  cut  off  with  a  sharp  knife,  and  the  skin  is  again 
immersed  in  cold  water.  The  portions  thus  removed 
may  be  set  aside  to  manufacture  glue. 

3.  The  hair  side  is  then  well  rubbed  and  smoothed 
down  with  a  stone,  similar  to  that  used  for  sharpening 
the  knife-blades,  but  which  is  set  in  a  wooden  handle. 
This  done,  the  skin  is  dipped  for  the  third  time  in  fresh 
water. 

4.  Both  sides  are  well  scraped  and  smoothed  with  a 
knife  having  a  curved  blade,  so  as  to  equalize  the  sur¬ 
faces  and  remove  all  foreign  substances. 

A  dozen  skins  can  be  worked  in  this  way  by  one  man 
in  the  course  of  a  day. 


SECTION  V. 

TANNING  PROCESS. 

Haying  completed  the  consideration  of  the  various 
operations  to  which  skins  are  subjected  before  they  are 
prepared  for  tanning,  we  proceed  to  give  an  account  of 
the  latter  process,  beginning  with  a  description  of  the 
vats  in  which  it  is  conducted. 


TAN  VATS. 


199 


CHAPTER  XXXVI. 

TAN  VATS, 

That  name  is  given  to  large  square  holes  excavated 
in  the  ground,  or  to  large  vats  in  oak  with  a  circular 
form.  The  first  are  still  in  use  in  several  countries  ; 
they  are  seven  and  a  half  feet  square  by  six  feet  deep. 
They  are  in  masonry,  and  covered  inside  with  a  kind  of 
mortar  made  with  lime,  sand,  and  cement.  In  Paris 
they  use  oak  vats  of  a  round  form  and  sunk  into  the 
ground.  The  latter  are  preferred  to  the  first,  and  are 
not  subject  to  the  same  inconveniences. 

1.  Whatever  care  is  taken,  those  in  masonry  always 
lose  some  of  the  infusion. 

2.  The  lime  of  the  cement  combines  with  the  tannin, 
and  forms  an  insoluble  tannate  of  lime. 

3.  The  vats  in  oak  wood,  carefully  made,  do  not  lose 
any  liquid. 

4.  Oak  wood,  instead  of  neutralizing  a  part  of  the 
tannin,  furnishes  to  the  liquor  a  new  quantity  of 
tannin. 

These  facts  should  induce  all  manufacturers  to  use 
them. 

All  tanners  do  not  operate  in  the  same  manner.  We 
shall  be  careful  to  indicate  all  the  little  changes  they 
have  made  in  the  common  process. 

After  the  skins  have  undergone  all  the  preliminary 
operations,  they  are  cut  in  two,  and  stratified  along 
with  tan  in  the  following  manner : — 

In  the  bottom  of  the  vat  put  a  bed  of  spent  bark, 
about  half  an  inch  thick,  cover  it  with  about  a  quarter 
of  an  inch  of  new  bark,  well  moistened,  and  place  a 
skin  on  the  top.  In  square  vats,  put  two  hides  in  one 
way  and  two  in  another,  and  set  across  them  a  fifth  one  ; 
but  in  circular  vats  lay  the  hides  all  round,  then  be 
careful  to  turn  exactly  at  the  right,  and  fix  them  so 
that  the  tail  of  the  last  rests  on  the  right  leg  of  the 
preceding.  By  following  this  process  a  vat  containing 
fifteen  or  sixteen  skins  can  be  filled  in  twelve  hours. 


200 


TANNING. 


On  the  first  layer  of  skin  spread  another  bed  of 
powder,  and  continue  thus  by  laying  alternately  a  bed 
of  powder  and  one  of  skin.  Be  careful  to  have  powder 
between  every  part  of  the  skin,  for  if  it  has  none  the 
skin  will  not  be  equally  tanned,  and  consequently  will 
not  be  equally  strong  and  solid.  Some  thicker  places 
require  more  bark,  but  the  shoulders  and  legs,  being 
thinner,  require  less. 

In  Paris  all  tanners  moisten  the  bark  before  using 
it.  For  this  purpose  they  throw  water  upon  it  and  mix 
it  thoroughly  with  a  shovel,  then  it  can  be  divided  more 
easily;  however,  some  manufacturers  use  it  just  as  it 
comes  from  the  mill.  The  Parisian  method  is  the  best, 
as  it  is  not  injurious  to  the  health  of  the  men,  who  by 
using  dry  powdered  bark  are  exposed  to  its  inhalation. 

In  speaking  of  the  tan,  we  have  said  that  the  English 
cracked  the  bark  ;  several  tanners  have  adopted  this 
process,  but  it  is  not  followed  everywhere.  It  is  gene¬ 
rally  admitted  that  the  first  ought  to  be  fine,  the  second 
a  little  coarser,  and  the  third  very  coarsely  ground. 

When  all  the  skins  are  laid  in  the  vat,  it  may  happen 
that  the  vat  is  not  entirely  full,  and,  whilst  the  skins 
have  been  uniformly  put  up,  some  empty  spaces  are 
found,  they  are  filled  with  powder ;  or  rather  when  you 
have  put  in  a  sufficient  quantity  of  new  powder,  distri¬ 
bute  it  so  that  the  surface  is  equal  all  over. 

In  small  tanneries  the  pits  are  not  always  filled  on 
the  same  day,  and  frequently  only  a  small  number  of 
hides  are  placed  in  them  at  a  time.  As  it  is  essential 
in  these  cases  that  they  should  be  kept  fully  moistened, 
more  water  should  be  added  each  time  that  the  new 
skins  are  deposited  in  them  ;  and  in  order  that  the  rela¬ 
tive  positions  of  the  contents  may  not  be  disturbed,  the 
surface  should  be  covered  with  a  coarse  cloth,  and  the 
water  carefully  poured  over  from  a  watering  pot,  and 
allowed  to  infiltrate  gradually. 

The  water  being  equally  distributed  through,  and  in 
sufficient  quantity,  the  vatting  of  the  pit  is  completed, 
lit  establishments  where  they  do  not  commence  vatting 
until  a  number  of  hides  sufficient  to  fill  the  vats  .has 


TAN  YATS. 


201 


been  prepared,  the  watering  should  be  completed  in  one 
operation.  When  this  is  the  case,  it  may  happen  that 
the  tan  rapidly  absorbs  all  the  water  poured  in,  and  in 
a  day  or  two  appears  perfectly  dry.  More  water  should 
then  be  added,  until  it  is  certain  that  the  vat  contains 
enough  to  moisten  all  the  hides  thoroughly.  The 
quantity  required  for  each  hide  is  about  12  gallons. 

When,  as  often  happens,  particularly  in  small  estab¬ 
lishments,  the  tanner  is  compelled  to  place  together  in 
the  same  vat  hides  in  different  states  of  progress,  that 
is,  those  of  the  first,  second,  and  third  treatment,  the 
following  mode  of  arranging  them  must  be  resorted  to. 
Those  of  the  third  treatment  are  to  be  deposited  at  the 
bottom,  those  of  the  second  above  them  in  the  middle, 
and  those  of  the  first  on  top  ;  so  that,  when  those  which 
have  gone  through  the  three  treatments  are  taken  out 
to  dry,  those  of  the  second  may  occupy  their  place  at 
the  bottom,  those  which  were  before  at  the  surface 
being  in  the  middle,  and  the  fresh  hides  which  are  to  be 
subjected  to  the  first  treatment  being  placed  at  the  top. 
This  convenient  method  promotes  an  equalization  of 
the  tanning, and  should  always  be  adopted;  because  the 
continued  exposure  of  the  same  set  of  hides  to  those 
parts  of  the  vats  which  possess  the  greatest  tanning 
power,  and  of  others  to  the  upper  strata  of  bark  which 
contains  the  least,  is  thus  avoided.  The  substances  at 
the  bottom  of  the  vat,  undoubtedly,  are  those  which 
possess  the  strongest  tanning  power,  because  the  de¬ 
scending  infusion,  passing  through  the  layers  of  tan 
above,  becomes  more  fully  impregnated  with  tannin  and 
extractive  matter  than  that  portion  which  remains  in 
contact  with  the  upper  strata  of  the  solid  materials. 
Moreover,  the  complete  penetration  and  combination  of 
these  matters  with  the  fibrine  and  gelatine  of  the  skins 
is  promoted  by  the  pressure  of  the  superincumbent 
hides,  the  tan,  and  the  column  of  fluid. 

When  the  ordinary  arrangement  is  adopted,  it  is  cus¬ 
tomary,  in  filling  the  second  vat,  to  place  at  its  bottom 
those  hides  which  have  been  at  the  top  of  the  first,  and 
so  on  through  the  ranges  of  vats.  This  is  done  for  the 


202 


TANNING. 


purpose  of  promoting  a  uniform  impregnation  of  all  the 
hides ;  since,  if  always  kept  in  the  same  position  in 
their  progress  through  the  yard,  those  occupying  the 
lowest  one  would  be  the  most  thoroughly  charged  with 
tannin. 

As  oak  bark  is  variable  in  quality,  it  is  scarcely  pos¬ 
sible  to  give,  with  certainty,  any  proportion  which  it 
should  bear  to  the  skins.  Skins  weighing  110  lbs.  usu¬ 
ally  require,  however,  about  double  that  amount  of  bark. 
From  33  to  44  lbs.  usually  suffice  for  each  of  the  skins 
from  Brescia,  which  do  not  commonly  weigh  more  than 
26  lbs.  Weak,  thin,  and  poor,  or  dry  hides,  being  of 
inferior  quality,  require  very  little  bark,  and  scarcely 
acquire  any  increase  of  substance.  Common  hides 
scarcely  ever  need  exposure  to  more  than  three  treat¬ 
ments,  the  first  being  given  upon  the  grain,  and  the 
others  upon  the  flesh  sides.  The  finest  powder  is  used 
for  the  first  process,  which  should  occupy  three  months. 
Coarser  stuff  is  employed  for  the  second,  which  should 
take  four  months,  while  the.  coarse  bark  alone  is  suf¬ 
ficient  for  the  third  exposure,  occupying  five  months. 
This  length  of  time  may  be  considered  sufficient  for  tan¬ 
ning,  though  the  best  tanners  extend  it,  giving  to  their 
hides  four,  or  for  the  best  qualities,  even  five  exposures 
in  the  pit. 

Fresh  hides  exhaust  the  tanning  ingredients  to  which 
they  are  exposed  in  the  first  process,  much  more  rapidly 
than  they  do  in  the  subsequent  ones ;  and  hence  the 
necessity  of  a  longer  treatment  in  the  second  and  third 
vats  than  in  the  first.  After  they  have  been  thoroughly 
fed  in  the  first,  further  contact  with  the  spent  materials 
would  be  useless,  as  these  are  almost  entirely  deprived 
of  activity;  and  it  may  be  very  injurious  to  them  by 
promoting  putrefaction.  In  passing  through  the  last 
vats,  however,  they  run  no  such  risks,  for  being  in  con¬ 
tact  with  strong  solutions  of  bark,  they  are  still  con¬ 
stantly — though  from  the  resistance  of  their  already 
tanned  surface  gradually — absorbing  tannin  and  acquir¬ 
ing  density.  Small  portions  of  alum  are  added  to  the 
tan  by  some  manufacturers,  with  the  intention  of  dimi- 


TAN  YATS. 


203 


nishing  the  impermeability  of  these  tanned  surfaces,  and 
hastening  the  process  in  its  latter  stage.  The  practice 
is,  however,  neither  a  common  nor  a  desirable  one. 

In  changing  hides  from  one  pit  to  another,  be  careful 
to  remove  from  their  surfaces  all  the  spent  tan  which 
covers  them,  so  that  there  may  be  no  mixture  of  effete 
matter  with  the  fresh  bark.  Some  tanners  even  take  the 
trouble  of  beating  and  shaking  the  hides  each  time  they 
are  changed. 

There  is  another  form  of  vat,  recently  invented,  and 
patented  by  J.  S.  Wheat,  of  Wheeling,  Va.,  who  makes 
the  following  statement: — 

“  I  have  my  tanning  process  in  full  operation  in  this 
city,  tanning  leather  in  one-tenth  of  the  time  required 
by  the  old  process,  and  I  warrant  the  leather  to  be  of 
the  finest  quality  for  wear.  This  process  combines  the 
handling  or  moving  of  the  hides  in  the  liquor,  the  circu¬ 
lation  of  the  liquor  through  the  vats,  the  pressure  upon 
the  hides,  and  the  circulation  of  the  liquor  through  the 
tan  bark  in  the  leaches,  all  at  the  same  operation,  and 
the  operation  may  be  suspended  upon  one  or  more  of  the 
vats  while  it  is  continued  in  the  others.  Therefore 
amongst  its  advantages,  in  addition  to  the  short  time 
consumed  in  tanning  leather,  is  the  great  saving  of  labor.” 

Fig.  42  is  a  perspective  view  of  the  apparatus,  and 
Fig.  43  is  a  horizontal  section  through  the  middle  of  the 
vats  combined  with  a  horizontal  section  through  the 
several  reservoirs. 

The  leather  is  placed  in  the  air-tight  cylindrical  vats 
X,X",X"',X"",  and  the  tanning  liquor  which  is  prepared 
by  mixing  water  with  bark  in  the  rectangular  reservoirs 
below,  is  made  to  circulate  through  the 
vats  by  means  of  a  force  pump  C.  The  liquor  in  the 
vat  is  subjected  to  pressure  regulated  by  a  weighed 
valve,  and  the  hides  are  forced  through  the  liquor  by 
being  placed  on  vibrating  frames  H  (Fig.  43)  within  the 
vats. 

The  water  is  mixed  with  the  bark  in  the  reservoirs 
E",E"\E"",E""',  and  these  reservoirs  have  perforated  false 


204 


TANNING. 


Fig.  42. 


bottoms  through  which  the  clear  liquor  is  strained  into 
the  lower  parts  of  the  reservoirs. 

From  these  places  it  is  drawn  out  by  means  of  the 
pump  through  branches  from  the  pipe  A,  which  pass 
through  the  ends  of  the  reservoirs,  and  are  bent  down 
so  as  to  extend  through  the  false  bottoms  into  the  clear 
liquor  below.  These  branch-pipes  are  provided  with 
stopcocks,  so  that  the  connection  between  any  one  of 
them  and  the  pump  may  be  opened  or  cut  off  at  will, 
and  thus  the  liquor  may  be  drawn  from  such  of  the  re¬ 
servoirs  as  the  operator  may  desire. 

From  the  pump  the  liquor  is  forced  into  the  vats 


TAN  VATS. 


205 


through  the  pipe  Z),  which  has  two  branches  leading 
into  the  bottoms  of  the  vats  X,X".  From  the  top  of 
vat  X  a  pipe  D "  leads  to  the  bottom  of  vat  X",  and  a 
pipe  F  leads  to  the  bottom  of  vat  X"'.  The  pipe  D'" 
leads  from  the  top  of  vat  X"  to  the  bottom  of  vat  X'", 
and  the  pipe  F"  leads  from  the  top  of  vat  X"  to  the  bot¬ 
tom  of  vat  X'"'.  A  pipe  D”"  leads  from  the  top  of  vat 
X'"  to  the  pipe  F"',  which  is  connected  with  the  top  of 
vat  X"".  All  of  these  pipes  are  furnished  with  stop¬ 
cocks,  so  that  any  vat  may  be  thrown  out  of  the  circu¬ 
lation  by  simply  opening  and  closing  the  proper  cocks. 

From  the  upper  end  of  pipe  F"  a  pipe  D"'"  leads  down 
to  the  reservoirs,  with  all  of  which  it  is  connected  by 
branch-pipes ;  each  branch  being  furnished  with  a  stop¬ 
cock. 

It  will  thus  be  seen  that  the  tanning  liquid  is  kept  in 
constant  circulation  through  the  vats  containing  the 
hides,  and  through  the  reservoirs  containing  the  bark  ; 
extracting  in  its  course  the  tannin  from  the  bark  and 
carrying  it  to  the  hides.  The  liquor  in  its  ascent  may 
be  passed  through  such  of  the  vats  and  reservoirs  as  the 
operator  may  desire  by  simply  turning  stopcocks. 

In  the  upper  end  of  the  pipe  F"\  but  below  the  exit 
of  pipe  D""',  is  a  valve  which  is  pressed  down  by  a  weight 
upon  the  lever  N.  By  setting  this  weight  at  the  proper 
point  upon  the  lever,  the  pressure  of  the  liquor  within 
the  vats  may  be  adjusted  to  any  desired  degree.  An 
emptying  pipe  G,  connected  with  the  bottoms  of  all  the 
vats  by  branch-pipes,  leads  into  the  reservoirs  F. 

The  frames  H,  in  the  vats,  are  hung  upon  shafts,  which 
pass  through  stuffing-boxes  in  the  ends  of  the  vats,  and 
they  receive  a  vibratory  motion  from  eccentrics  on  the 
pump-shaft,  with  which  they  are  connected  by  levers  in 
such  a  manner  that  by  simply  lifting  the  levers  out  of 
connection  the  action  of  the  frame  in  any  vat  may  be 
suspended.  The  hides  are  introduced  into  the  vats 
through  manholes  provided  for  the  purpose. 


206 


TANNING. 


CHAPTER  XXXVII. 

HEALD’S  APPARATUS  FOR  TANNING  HIDES. 

w  M.  H.  Heald,  of  Baltimore,  invented  and  patented, 
in  1860,  an  apparatus  for  tanning  hides.  We  give  below 
a  description  of  its  construction  and  operation.  The 
Fig.  44  represents  a  perspective  view  of  said  apparatus. 

Fig.  44. 


Figure  45  represents  a  longitudinal  vertical  section 
through  the  same. 

The  work  of  repeatedly  raising  the  hides  from  the  vat, 


heald’s  apparatus  for  tanning  hides.  207 

for  the  purpose  of  exposing  them  to  the  air,  constitutes 
one  of  the  most  laborious  tasks  in  the  operation  of  tan¬ 
ning.  This  invention  relates  to  the  construction  of  an 
apparatus  to  which  the  hides  are  united  in  such  a  man¬ 
ner  that  they  will  hang  loosely  and  vertically  in  the 
vat,  and  may  be  raised  from  the  vat  with  facility,  and, 

Fig.  45. 


when  raised,  lie  in  a  pile,  and  the  drippings  therefrom 
all  run  back  into  the  vat. 

To  enable  others  skilled  in  the  art  to  make  and  use 
this  invention,  we  shall  proceed  to  describe  its  construc¬ 
tion  and  operation. 

A  represents  the  vat  which  contains  the  tan-liquor. 


208 


TANNING. 


B  represents  a  triangular  frame,  which  is  suspended 
within  said  vat  by  means  of  ropes  or  chains  C,  and  which 
can  be  raised  or  lowered  by  turning  the  crank  D ,  and 
the  drums  _E,  around  which  the  ropes  or  chains,  C,  are 
wound.  The  frame,  B,  has  grooves,  a,  cut  on  its  inner 
sides,  into  which  the  ends  of  the  bar,  b,  are  inserted. 
The  hides,  c,  to  be  tanned  are  hung  over  these  bars,  as 
represented  in  Fig.  45,  and  one  or  more  such  grooves 
may  be  used  for  securing  the  bars  therein.  When  three 
such  grooves  are  used,  the  hides  may  be  suspended,  as 
represented  in  Fig.  45,  where  the  bar  of  each  consecu¬ 
tive  hide  is  inserted  in  a  different  groove,  by  which 
arrangement  they  can  be  inserted  and  removed  with 
greater  facility  than  when  they  are  all  inserted  in  one 
groove,  and  when  they  are  packed  closely  together. 
The  frame,  B,  has  pivots,  g,  at  its  side,  which  slide  in 
corresponding  grooves,  h,  in  the  sides  of  the  vat,  and 
which  cause  the  frame  to  move  perpendicularly  on  being 
raised  or  lowered.  When  the  frame  is  to  be  raised  for 
the  purpose  of  exposing  the  hides  to  the  air,  or  for  re¬ 
moving  them,  the  crank  D  is  turned,  and  the  frame  B 
rises,  and  as  the  sides  near  the  pivots,  g ,  is  somewhat 
heavier  than  its  opposite  side,  the  frame  will  lean  to¬ 
wards  that  side,  and  when  arrived  at  the  top  of  the  vat, 
it  will  be  raised  on  the  edge  of  the  side  of  the  vat,  as 
represented  in  a ,  b ,  Fig.  45,  and  may  then  be  raised 
to  any  degree  of  inclination,  or  almost  to  a  horizontal 
position,  leaving  just  sufficient  inclination  for  the  drip¬ 
pings  to  run  back  into  the  vat.  The  frame  in  this  posi¬ 
tion  may  be  secured  by  braces,  stops,  or  their  equivalents. 
To  prevent  the  frame  from  being  raised  out  of  the 
groove,  A,  by  inadvertence,  the  stop  pins,  m,  may  be 
used,  by  which  the  motion  of  the  frame  is  arrested  as 
soon  as  the  pivots,  g,  come  in  contact  with  them.  By 
this  apparatus  the  hides,  when  once  hung  within  the 
frame  B,  do  not  require  any  further  handling,  and  can 
be  raised  and  lowered  with  facility,  thus  saving  a  great 
amount  of  labor  in  the  operation  of  tanning;  and  when 
frame  B  arrives  in  the  position  shown  in  Fig.  44  the 
hides  lie  on  top  of  each  other  in  a  pile,  and  may  be 


TIME  NECESSARY  FOR  TANNING. 


209 


conveniently  removed.  In  this  position,  too,  the  frame 
is  more  readily  filled  with  hides,  as  it  is  comparatively 
clear  of  the  vat,  though  ready  to  turn  into  it  when  de¬ 
sired.  In  the  mere  handling  of  the  hides  these  machines 
save  much  labor,  as  they  can  be  immersed  in  the  vat  or 
raised  out  again  into  a  pile,  whence  they  can  be  removed 
and  others  put  in  their  place. 

From  the  time  the  hides  are  placed  in  the  frames  un¬ 
til  they  are  ready  to  be  laid  away  in  bark,  is  six  weeks, 
thus  saving  four  or  five  weeks  over  the  old  style  of 
reels. 


CHAPTER  XXXVIII. 

TIME  NECESSARY  FOR  TANNING. 

The  importance  of  discovering  some  process  which 
should  shorten  the  time  usually  occupied  in  tanning, 
without  injuring  the  beauty  and  durability  of  the  lea¬ 
ther,  and  which  should  also  diminish  the  expense  of  the 
manufacture,  by  substituting  some  less  costly  materials 
for  oak  bark,  has  long  been  appreciated  by  chemists  and 
practical  men. 

Among  others,  who  have  devoted  much  attention  to 
this  subject,  is  Seguin,  who,  acting  upon  his  opinion  that 
the  combination  of  tannin  with  the  gelatine  and  fibrine 
of  skins  might  be  much  accelerated  by  presenting  it  to 
them  in  a  liquid  and  concentrated  form,  succeeded  in 
greatly  shortening  the  time  required  for  tanning.  But 
experience  has  shown  that,  though  the  leather  prepared 
by  such  means  is,  to  all  appearances,  well  tanned,  it  does 
not  possess  the  requisite  quantities.  It  is  not  thoroughly 
and  uniformly  impregnated ;  for,  while  the  outer  layers 
of  the  two  surfaces  combine  rapidly  with  tannin,  a  de¬ 
posit  of  gallic  acid  and  extractive  matter  forms  a  com¬ 
pact  coating,  which  prevents  their  complete  penetration, 
and  renders  their  interior  inaccessible  to  the  liquid. 
This  leather  is  dry,  and  by  no  means  durable,  its  inte¬ 
rior  consisting  of  untanned  hides.  We  shall  speak  of 
it  in  treating  of  Seguin’s  process. 

14 


210 


TANNING. 


Experience  has  shown  that,  to  insure  the  perfection  of 
leather,  all  the  gelatine  and  fibrine  of  the  original  skins 
must  be  made  to  combine  with  tannin,  and  that  this 
combination  must  be  effected  in  the  most  gradual  way, 
the  accomplishment  of  which  is  only  to  be  procured  by 
exposures  to  solutions,  which  at  first  are  weak  and  after¬ 
wards  are  increased  in  strength,  until  at  last  complete 
saturation  is  arrived  at.  After  this  entire  conversion  of 
substance  has  been  attained,  further  exposure  only  serves 
to  injure  the  texture  of  the  hide  by  introducing  into  it  a 
dry,  hard,  and  horny  matter,  which  renders  them  brittle 
and  easily  penetrable  by  moisture,  and  to  consume  use¬ 
lessly  the  time  and  money  of  the  manufacturer. 

If,  on  the  contrary,  they  have  been  exposed  too  short 
a  time,  they  will  be  imperfect  and  wanting  in  the  requi¬ 
site  weight  and  solidity.  It  is  therefore  an  established 
fact  that  12  or  18  months  are  required  for  the  complete 
tanning  of  the  best  qualities  of  hides,  they  being  found 
to  increase  in  strength  and  weight  up  to  the  end  of  that 
time,  which  is  the  usual  duration  of  the  process  in  Eng¬ 
land  as  well  as  in  this  country.  Still  there,  as  well  as 
here,  skins  are  often  sent  into  the  market  after  an  ex¬ 
posure  of  six  or  ten  months,  and  even  less. 


CHAPTER  XXXIX. 

PROPORTIONS  OF  THE  BARK  USED. 

The  proportions  of  bark  required  vary  considerably, 
according  to  the  species,  the  quality  and  destination  of 
the  hides.  For  the  skins  of  the  butchers  in  Paris, 
weighing  112  lbs.,  at  times  from  336  to  393  lbs.  of  tan 
are  used.  Sometimes  292  lbs.  divided  into  four  parts 
are  sufficient,  90  for  the  first  and  67  for  the  others. 

In  the  provinces  of  France  they  vary  much  in  weight. 
At  Bordeaux  the  liquors  are  strong,  while  in  Brittany 
they  are  weak.  In  some  places  they  do  not  use  less  than 
675  lbs.  of  bark  for  225  lbs.  of  fresh  skin,  the  weight 
of  which  after  tanning  has  increased  to  337  pounds. 


DRYING  OF  THE  LEATHER. 


211 


CHAPTER  XL. 

DRYING  OF  THE  LEATHER. 

The  drying  of  the  leather,  however  simple  a  process 
it  may  appear,  requires  the  utmost  skill  and  attention 
on  the  part  of  the  workmen,  and  the  nicest  determination 
of  the  point  to  which  it  should  be  carried.  Skins  dried 
too  slowly,  and  in  moist  situations,  are  liable  to  mould, 
which  is  greatly  to  their  injury,  while  those  which  are 
dried  too  rapidly,  or  during  exposure  to  the  direct  rays 
of  the  sun,  become  hard  and  brittle. 

In  order  to  prevent  either  of  these  extremes,  every 
factory  should  have  attached  to  it  a  drying-room  pro¬ 
portioned  to  its  wants,  in  which  numerous  openings  or 
windows  admit  a  free  current  of  air,  while  the  leather  is 
protected  from  the  direct  influence  of  solar  heat. 

The  skins,  when  sufficiently  tanned,  are  to  be  taken 
from  the  pits  without  being  shaken  or  beaten,  and  are 
to  be  stretched  on  pegs  or  hung  up  by  their  heads  from 
large  nails,  each  one  being  kept  expanded  by  two  or  three 
sticks  passed  through  from  side  to  side,  so  that  all  parts 
may  be  uniformly  exposed  to  the  air.  When  they  have 
begun  to  whiten  and  have  become  slightly  stiff,  but 
before  they  are  perfectly  dry,  they  are  stretched  out 
upon  a  clean  place  and  scoured  with  the  spent  tan  with 
which  they  are  still  covered.  When  well  cleaned  in 
this  way,  they  are  then  to  be  trod  out  and  beaten  with 
the  soles  of  the  feet  in  every  direction,  upon  both  sides ; 
and  after  the  inequalities  and  protuberances  of  surface 
have  been  made  to  disappear  by  this  flattening  process, 
they  are  assorted  in  sizes  and  piled  up  in  heaps. 

While  the  skins  are  stretched  in  the  drying-room, 
they  should  be  beaten  twice  daily,  at  morning  and  eve¬ 
ning,  upon  the  flesh  side  with  a  round-face  wooden  mal¬ 
let.  If  the  skins  should  be  dry,  the  operation  may  be 
facilitated  by  moistening  their  surface  with  a  wet  brush. 
This  process  imparts  firmness. 

The  Shoe  and  Leather  Reporter  has  lately  published  a 


212 


TANNING. 


very  good  article  on  the  drying  of  tanned  leather,  an 
extract  of  which  we  think  will  interest  the  reader. 

“  To  overcome  difficulties,  we  must  first  appreciate 
them.  The  difficulties  and  delays  in  drying  leather  as 
above  described  are  very  great.  The  amount  of  leather 
which  tanners  require  to  have  in  the  loft  exposed  to  the 
risk  of  fire  is  always  very  large,  and  at  particular  seasons 
of  the  year  so  large  that  some  find  it  difficult  to  obtain 
the  requisite  amount  of  insurance,  even  at  a  very  high 
rate  of  premium. 

“We  think  it  quite  within  our  experience  to  state 
that  a  tanner  turning  out  150  sides  per  day  must  have 
exposed  about  5,000  sides ;  which  at  2h  per  cent,  would 
amount  to  $500  a  year  for  the  item  of  insurance.  The 
loss  of  interest  and  inconvenience  of  delay  must  also  be 
added,  to  appreciate  fully  the  difficulties  experienced 
under  our  present  system. 

“  We  hope  to  be  able  to  show  that  no  tanner  need  have 
over  1000  sides  exposed  at  any  one  time,  to  enable  him 
to  roll  and  furnish  150  or  even  200  per  day.  This  esti¬ 
mate,  it  will  be  perceived,  would  cover  a  first  class  tan¬ 
nery. 

“To  make  this  improvement  of  practical  value,  it  must 
be  adapted  to  our  present  buildings.  But  if  we  describe 
a  perfect  drying  loft,  the  features  which  are  new  will 
be  appreciated,  and  may  be  applied  to  each  tanner  as 
his  circumstances  may  permit. 

“  The  building  should  be  as  high  as  possible,  not 
certainly  less  than  twenty,  and  if  fifty  feet  from  the 
base  floor  to  the  peak,  all  the  better. 

“  The  lower  floor  should  be  closed  against  the  damp¬ 
ness  of  the  yard,  or  if  placed  on  the  ground,  from  the 
moisture  which  would  arise.  No  opening  or  window 
should  be  allowed  except  from  the  lower  part  imme¬ 
diately  over  the  base  floor,  and  this  opening  should  be 
by  a  board  trap  opening,  say  of  one  foot  wide,  so  hung 
on  hinges  as  to  be  easily  regulated,  and  should  extend 
all  around  the  building.  The  other  opening  should  be 
in  the  extreme  peak  of  the  building,  and  should  also 
be  so  constructed  as  to  be  easily  opened  and  closed. 


DRYING  OF  THE  LEATHER. 


213 


A  drying  loft  thus  constructed  will  always,  by  its  own 
action,  have  a  draft  passing  through  it,  even  when  the 
outside  weather  would  indicate  that  there  was  no  air 
stirring. 

“  In  ordinary  drying  weather  such  a  loft  will  dry  wet 
leather  from  the  vats  in  five  or  six  days.  But  this  will 
not  of  itself  accomplish  what  we  want.  We  must 
have  some  artificial  means  of  drying  when  the  weather 
is  not  favorable. 

“  This  artificial  heat  can  in  no  way,  in  our  judgment, 
so  satisfactorily  be  applied  as  by  steam  pipes.  These 
are  the  best  distributors  of  heat  of  any  that  have  yet 
been  applied. 

“  Heat  or  dry  air  can  be  forced  by  blowers  into  a  loft, 
but  to  do  this  effectually  considerable  power  is  required. 
Steam  pipes,  when  properly  laid,  are  self-acting,  and 
distribute  heat  more  gently  and  uniformly  than  stoves, 
however  placed. 

“  Some  of  the  conditions  to  be  observed  are  the  fol¬ 
lowing  :  The  boiler  which  generates  the  steam  must  be 
lower  than  the  base  floor.  The  opening  from  which 
the  escape  steam  pipe  should  enter  should  be  from  the 
top  of  the  boiler,  and  the  return  pipe  should  enter  at 
the  bottom ;  when  thus  placed,  there  will  be  none  of 
that  bursting  of  pipe  of  which  we  hear  so  much. 

“  The  pipe  should  be  as  nearly  as  possible  on  a  level 
or  incline  towards  the  boiler,  so  that  the  condensed 
steam  or  water  will  run  freely  in  that  direction,  but 
where  eight  or  ten  pounds  of  steam  pressure  is  kept  on 
the  boiler,  little  difficulty  need  be  apprehended.  It  is 
only  when  there  is  no  pressure  of  steam  that  the  water 
freezes  in  the  pipe  and  gives  trouble. 

“  But  we  omit  practical  details,  since  no  tanner  will 
attempt  to  adopt  this  improvement  without  consulting 
a  practical  pipe  fitter,  and  they  are  now  to  be  found  in 
most  every  town. 

“  Experience  has  indicated  that  about  five  thousand* 
feet  of  pipes  properly  laid  will  do  all  the  drying  that 
any  ordinary  tanner  will  require  at  eight  pounds  pres¬ 
sure.  This  pipe  should  be  laid  on  the  floor  as  near  the 


214 


TANNING. 


centre  as  possible,  and  not  around  the  sides  of  the 
building,  as  some  have  placed  it.  The  pipe  to  be 
covered  with  lattice  wood  work  to  prevent  disturbance. 

“  Experience  may  show  that  the  side  may  be  the 
proper  place  to  fasten  the  pipe  if  placed  opposite  and 
inside  the  opening  of  which  we  have  spoken ;  for  the 
current  of  air  from  the  outside  may  be  sufficiently  strong 
to  force  the  heated  or  dry  air  to  the  centre,  and  thus 
form  a  current  up  to  the  top  opening.  But  we  are  sure 
without  such  opening  the  air  forms  a  current  up  the 
side  of  the  building,  and  does  not  penetrate  the  centre. 

“  The  effect  of  side  openings,  other  than  the  kind 
here  recommended,  is  to  create  counter  currents  and 
destroy  the  whole  effect. 

“  This  whole  subject  is  both  new  and  interesting.  We 
do  not  think  there  is  any  novelty  in  the  use  of  steam 
pipes  in  drying  lofts.  But  we  think  that  most  of  the 
effect  has  been  lost  heretofore  by  reason  of  the  improper 
construction  of  the  loft. 

“  We  think  that  a  tanner  may  run  partitions  inclosing 
three  or  four  bents  of  his  tannery,  from  base  floor  to  the 
peak,  and  dry  more  leather  in  these  few  bents  than  he 
does  now  in  his  whole  loft. 

“  With  a  proper  heating  apparatus  in  connection  with 
a  properly  constructed  drying  loft,  sole-leather  wet  from 
the  vats  can  be  dried  in  forty-eight  hours,  ready  for  the 
roller.” 


CHAPTER  XL  I. 

BEATING  OF  THE  LEATHER. 

After  the  skins  have  remained  in  pile  for  a  day,  they 
are  exposed  to  the  air,  as  before,  for  four  days.  When 
nearly  dry,  they  are  taken  down  and  pressed  under 
planks  heavily  loaded  with  large  stones.  The  next  day 
they  are  spread  out  upon  an  oak  or  marble  table 
and  beaten  with  an  iron  mallet,  so  as  to  compress  their 
tissue  and  render  them  smooth  and  compact.  The 
operation  is  performed  as  shown  in  the  figure. 


BEATING  AND  ROLLING  BY  MACHINERY. 


215 


This  proceeding  should  never 
be  omitted,  whatever  may  have 
beep  the  original  preparation  of 
the  skins  for  the  vat.  Lime  hides 
should,  however,  be  treated  before 
they  are  dried,  as  otherwise  the 
hair  side  surface  would  be  ex¬ 
posed  to  the  danger  of  being  broken 
and  rendered  uneven. 

The  process  of  beating  leather  is 
essential  to  give  it  firmness  and 
durability,  and  to  make  it  impervious  to  moisture.  It 
is  only  the  first  step  of  the  manipulation  which  the  shoe¬ 
maker  finds  it  so  necessary  to  continue  upon  the  lap- 
stone. 

The  leather,  after  being  thus  hammered,  is  now  tho¬ 
roughly  dried  for  the  last  time,  and  piled  up  in  a  dry 
and  well-ventilated  loft.  Before  it  is  ready  for  market, 
the  leather  should  be  repeatedly  shuffled,  as  it  were  ;  that 
is,  the  position  of  each  hide  must  be  changed,  and  the 
piles  spread  out  in  the  manner  of  an  open  fan,  and 
pressed  as  before,  under  planks  and  superincumbent 
weights. 

Having  undergone  these  different  processes  for  nearly 
a  month,  it  is  again  piled  preparatory  to  being  sent  into 
the  market.  Not  satisfied  with  this  management  of  it, 
some  tanners  even  take  the  unnecessary  trouble  of  stor¬ 
ing  it  away  in  cellars  for  some  time  before  they  consider 
it  thoroughly  seasoned. 


Fig.  46. 


CHAPTER  XLII.  . 

BEATING  AND  ROLLING  BY  MACHINERY. 

The  process  described  above  was  a  tedious  and  labo¬ 
rious  mode  of  operating,  which  is  rarely  resorted  to  now, 
and  has  been  superseded  by  machinery.  The  principal 
object  of  these  machines  was  to  accelerate  the  process 
and  diminish  the  labor,  and  afterwards  it  was  found  that 
they  also  accomplished  the  desiderata  of  imparting 


216 


TANNING. 


smoothness,  compactness,  and  uniform  thickness  to  the 
leather. 

In  the  earlier  stages  of  this  invention  the  imperfection 
of  the  machinery  rendered  it  necessary  to  finish  the 
beating  by  hand,  but  improvement  grew  with  experience 
and  has  resulted  in  some  perfect  apparatus. 

Sterlingue  &  Co.  were  the  pioneers  in  this  branch  of 
ingenuity,  and  proposed  the  use  of  a  hammer  like  those 
employed  for  forging  iron,  but  grooved,  and  an  anvil 
faced  with  brass.  The  other  portions  of  their  machine 
are  a  table  for  receiving  the  hides  and  cylinders  for  the 
cords  or  straps  which  kept  the  leather  extended,  their 
axes  being  connected  with  an  endless  chain  in  such  a 
manner  that  the  straps  which  are  rolled  upon  them  on 
one  side  are  unrolled  on  the  other. 

The  hides  are  allowed  to  be  at  rest  during  the  descent 
of  the  hammer,  and  are  moved  from  under  it  during  its 
elevation.  The  blows  may  be  increased  in  frequency 
and  force  at  the  will  of  the  operator,  and  if  it  is  thought 
proper  to  direct  a  number  of  blows  upon  one  part  of  the 
hides,  the  movement  can  be  suspended  by  a  catch  until 
the  required  number  has  been  applied. 

Having  found  that  the  horizontal  position  of  the  ham¬ 
mer  interfered  somewhat  with  the  motion  of  the  hides, 
they  substituted  a  vertical  hammer,  like  a  pile-driver. 
By  this  improvement  they  obtained  the  alternate  and 
successive  action  of  a  number  of  hammers  upon  the 
leather,  and  established  a  system  by  which  rows  of 
hammers  of  moderate  weight  are  so  arranged  that  those 
of  the  second  row  descend  upon  the  prolongation  of  a 
line  oblique  to  that  of  the  first  one,  and  fall  upon  the 
hides  with  a  constantly  increasing  force. 

Debergue's  Machine. — This  machine,  invented  in  1840, 
is  described  in  vol.  lvi.  p.  40,  plate  4,  of  French  Reports 
of  Expired  Patents. 

Figs.  47  and  48. 

«,  a.  Pulleys,  for  communicating  movement. 

b.  Longitudinal  iron  shaft. 

c.  c.  Cast  framework,  supporting  the  shafts  b  and  g. 

d.  Cast  support,  for  the  end  of  the  shaft  b. 


BEATING  AND  ROLLING  BY  MACHINERY. 


217 


e ,  e.  Pinions,  gearing  with  the  wheels  f,  f 
g.  Iron  shaft,  carrying  the  wheels  f,  f,  outside  of  the 
framework. 


Fig.  41. 


h,  h.  Crank-rods,  the  iron  pivots  of  which,  i,  i,  are 
fixed  by  means  of  nuts  in  grooves  cut  in  the  wheels  /,/, 
so  that  their  position  can  be  changed  at  pleasure. 

j.  Iron  shaft,  receiving  an  oscillating  motion  from  the 
cranks  h  and  h. 

k.  Cast-iron  lever,  carrying  at  its  lower  extremity  a 
stamper  or  small  cylinder  in  a  fork,  and  having  passing 
across  it  the  shaft  j,  the  movements  of  which  it  follows. 

The  upper  part  of  this  lever  is  equally  divided  into 
two  branches,  in  each  of  which  is  a  groove  traversed  by 
the  iron  shaft  m,  fixed  at  its  extremities  to  double  cast 
supports  n ,  n.  Above  these  grooves  there  are  two  rests, 
o ,  o ,  for  the  cast-iron  lever  p,  which  pivots  upon  the 


218 


TANNING. 


Fig.  48. 


trunnions  q,  q,  and  to  the  extremity  of  which  is  attached 
an  iron  rod  which  supports  a  cast  box  or  iron  plate,  or 
else  a  wooden  box  which  can  be  weighted  if  necessary. 
Upon  the  line  marked  by  the  rest,  the  lever  can  be 
moved  over  the  whole  space  between  the  two  supports, 
and  this  part  should  be  accurately  adjusted,  so  that, 
whatever  may  be  its  position,  the  lever  will  weigh  uni¬ 
formly  upon  the  rest.  r.  Iron  shaft,  adjusted  between 
the  two  supports  n ,  n,  and  resting  at  the  other  end  upon 
a  simple  support  s.  The  screw  passes  through  the  cast 
piece  t ,  forming  its  nut,  and  having  two  projections 
pierced  to  receive  the  shaft  m,  upon  which  it  moves 
when  the  screw  is  turned.  As  the  projections  of  the 
nut  t  entirely  fill  the  interval  between  the  branches  of 
the  lever  k,  this  lever  must  follow  the  movements  of  the 
nut  exactly  as  if  directly  commanded  by  the  screw,  w, 
u  are  two  pulleys,  across  which  passes  the  uncut  part  of 


BEATING  AND  ROLLING  BY  MACHINERY. 


219 


the  screw  z.  These  pulleys  are  commanded  by  the  other 
pulleys  v ,  v,  the  one  by  a  straight  strap,  the  other  by  a 
crossed  one,  and  are  turned  in  an  opposite  direction  to 
each  other. 

oc.  Toothed  shaft  partaking  of  the  rotatory  motion  of 
the  main  shaft,  which,  being  traversed  by  a  pin,  but 
being  movable  to  the  right  or  left  at  pleasure,  and  fitting 
in  the  claws  of  the  pulleys  n,  n ,  renders  their  movement 
uniform  with  that  of  the  shaft.  At  the  middle  of  this 
shaft  there  is  a  large  groove,  which  receives  two  small 
iron  stays,  fixed  to  the  interior  of  the  oval  which  the 
lever  y  forms  at  its  junction  with  the  shaft.  This  lever 
is  surmounted  by  a  ballw,  and  is  mounted  upon  an  iron 
pivot,  which  is  fixed  upon  the  cross-piece  a\  fastened  at 
its  extremities  to  the  support  n,  n. 

b'.  Round  iron  rod  having  a  square  part  at  the  end 
which  slides  in  one  of  its  supports,  and  is,  by  this  means, 
prevented  from  being  turned.  This  rod  passes  across  a 
tail-piece,  attached  to  the  nut  t,  and  carries  two  rings,  c' 
c',  fastened  at  a  convenient  part  by  a  compressing  screw. 
The  rod  also  has  upon  it  two  little  projections,  d'  d\ 
which  engage  the  lever  y,  and  give  it  an  alternate  motion 
to  the  right  or  left,  when  the  tail  of  the  nut  encounters 
alternately  the  rings  c'  c'. 

e' .  Cast,  marble,  or  wooden  table,  surmounted  by  a 
copper  plate.  The  table,  as  the  plan  shows,  may  be 
either  plane  or  concave,  without  any  injury  to  the  suc¬ 
cess  of  the  process  following.* 

This  machine  is  intended  to  produce  the  most  com¬ 
plete  contraction  of  the  pores  of  leather  that  can  be 
attained,  by  means  of  two  different  movements  combined 
in  one,  and  by  a  pressure  of  from  18  to  20  thousand 
weight  upon  a  surface  of  some  fractions  of  an  inch,  this 
pressure  being  transmitted  through  the  whole  thickness 

*  It  will  be  observed  that  an  occasional  discrepancy  between  the 
lettering  of  the  cuts  and  the  references  to  them  in  the  description 
occurs  in  this  and  a  few  other  instances  throughout  the  work.  The 
errors  are  to  be  met  with  in  the  original  French  treatise  much  more 
frequently  than  in  the  present  edition  ;  and  those  which  have  not  been 
altered  from  the  originals  by  the  engraver,  will  be  detected  at  once 
by  any  machinist. 


220 


TANNING. 


of  the  skins  without  injuring  or  abrading  their  surfaces, 
and  compressing  those  of  different  thickness  with  entire 
uniformity. 

The  hides  are  placed  upon  the  table  e;  the  stamper  l, 
to  which  a  round,  oval,  curved,  or  straight  form  can  be 
given  at  pleasure,  directed  by  the  whole  weight  of  the 
lever  k ;  and  the  additional  one  of  the  lever  p,  passes  over 
the  leather  and  receives  the  oscillating  motion  given  to 
the  lever  k ,  by  the  cranks  h,  h.  *It  also  receives  another 
motion  which  makes  it  pass  progressively  across  the 
breadth  of  the  table,  first  in  one  direction  and  afterwards 
in  the  other,  and  which  is  caused  by  the  screw  which 
receives  an  alternate  rotatory  motion  to  the  right  and  to 
the  left,  by  means  of  the  toothed  shaft  which  catches  in 
the  pulleys  to  the  right  and  to  the  left,  being  governed 
by  the  lever  with  the  ball  on  top,  which  is  drawn  away 
from  its  centre  of  gravity  by  the  projections  d',  d',  of  the 
rod  b ,  and  falls  back  upon  the  opposite  side. 

The  table  being  higher  on  one  side  than  on  the  other, 
and  the  course  of  the  lever  passing  the  curved  part 
where  it  is  least  elevated,  the  stamper  leaves  the  surface 
of  the  leather  at  short  intervals,  which  are  determined 
by  each  revolution  of  the  wheels  /,  /,  and  the  pressure 
being  thus  taken  off,  the  leather  can  be  moved  by  the 
workman  and  replaced  in  another  position,  so  that  the 
force  can  be  directed  successively  upon  the  whole  sur¬ 
face. 

The  results  of  this  operation  are  an  immense  economy 
of  time,  labor,  and  trouble,  the  greatest  possible  amount 
of  compression  and  contraction  of  the  substance  of  the 
leather,  the  securing  of  a  perfectly  uniform  and  smooth 
surface,  and  the  accomplishment  by  one  workman  of 
what  can  only  in  common  be  effected  by  ten  or  twelve. 

Flotard  and  Delbufs  Machine. — The  following  is  a 
description  of  a  machine  invented  in  1842,  by  Flotard 
and  Delbut,  taken  from  the  Reports  of  Expired  French 
Patents,  vol.  lvii.  p.  86;  its  object  being  to  replace  hand 
beating  by  more  active  means,  which  will  be  free  from 
the  inconveniences  attaching  to  other  machines.  To 
attain  this  end,  the  inventors  have  endeavored  chiefly: — 


BEATING  AND  ROLLING  BY  MACHINERY. 


221 


1st.  To  bring  to  perfection  the  construction  of  the 
mechanism  moving  the  hammer,  and 

2d.  To  make  the  anvil  elastic,  so  that  injury  to  the 
leather  by  the  hardness  and  roughness  of  the  blows  may 
be  prevented. 

3d.  To  use  a  table  with  a  rolling  surface,  and  with 
rollers  attached  to  the  feet. 

Figs.  49,  50,  and  51.  a.  Cam,  intended  to  lower  the 
arm  of  the  lever,  c,  so  as  to  elevate  the  hammer  e. 


Fig.  49. 


b.  Framework,  or  cast  beam,  supported  on  three  co¬ 
lumns  and  sustaining  the  whole  apparatus. 

c.  Lever,  having  one  extremity  furnished  with  a 
wooden  cushion,  and  the  other  rounded  off  to  enable  it 
to  move  freely  in  the  mortice  of  the  hammer. 

d.  Cast  arm,  the  end  of  which  holds  the  helve  of  the 
hammer  and  maintains  it  in  the  vertical  position. 

e.  Hammer,  having  its  lower  surface  covered  with 
copper. 

f  Support,  or  anvil,  composed  of  two  principal  parts: 
the  one  fastened  to  the  ground,  1,  is  furnished  with  a 


222 


TANNING. 


grating,  2,  which  receives  the  fuel,  and  is  attached  by 
screws  to  masonry- work;  the  other  part,  4,  is  that  which 


Fig.  51. 


receives  the  impulse  of  the  hammer.  It  is  movable, 
and  mounted  on  twelve  springs,  3 ;  and  its  upper  sur¬ 
face  is,  like  the  opposing  one  on  the  hammer,  composed 
of  copper. 

g.  Fly-wheel,  connected  with  the  motive  power  by 
means  of  a  band. 

Figs.  52  to  55.  Hammer,  of  cast  or  wrought  iron.  If 
sufficiently  small,  it  may  be  solid,  but  if  large,  should  be 
hollow. 

a,  a'.  Wooden  teeth,  against  which  the  cam  b  catches. 
These  teeth  are  adapted  to  two  mortises  in  the  upper 
part  of  the  hammer,  and  are  retained  in  place  by  a 
wooden  wedge.  By  means  of  the  two  teeth,  the  ham¬ 
mer  can  be  elevated  more  or  less,  either  by  taking  off 
the  lower  one  a',  or  by  enlarging  or  diminishing  their 
size. 

b.  Cam,  acting  upon  the  teeth  a,  to  elevate  the  ham¬ 
mer. 

d.  Cylinder,  directing  the  hammer  and  keeping  it  ver¬ 
tical.  This  is  furnished  with  two  projections  3,  which 
support  cushions  for  the  shaft  of  the  cam  b.  It  rests 
upon  a  shoulder  d’,  upon  the  plate  b’.  The  lips  i,  i, 
against  which  the  wooden  teeth  slide,  prevent  the  ham¬ 
mer  from  turning. 

Two  lateral  openings,  o,  o,  Fig.  53  (also  seen  in  Fig. 
52),  allow  the  cushions  r,  r  (Fig.  54)  to  pass,  which 
press  the  levers  l,  I,  worked  by  a  screw,  to  the  right  at 


BEATING  AND  ROLLING  BY  MACHINERY. 


223 


one  end,  and  to  the  left  at  the  other.  Fig.  52  exhibits 
this  arrangement. 


Fig.  52. 


Fig.  53.  Fig.  54. 


The  shaft  m,  Fig.  54,  serves  as  a  prolongation  of  the 
screw  n ,  Fig.  53,  and  carries  a  pulley  v ,  Fig.  52,  upon 


224 


TANNING. 


which  passes  a  cord  having  a  weight  at  one  end,  and  a 
stirrup  for  the  foot  at  the  other.  The  cushions  r,  r  pro- 
duce  a  friction  which  slackens  the  fall  of  the  hammer, 
and  diminishes  the  force  of  the  blow. 

d'.  Circular  plate  or  cup,  intended  to  receive  the  oil 
or  grease  dripping  from  the  machinery,  and  which  might 
otherwise  fall  upon  and  soil  the  leather.  Fig.  51.  Two 
vertical  pieces,  supporting  horizontally  a  rabbit,  or 
wooden  spring,  which  is  elevated  or  depressed  by  the 
screw  attached  to  one  end  of  it,  so  that  the  hammer  a, 
in  rising,  touches  it  with  more  or  less  force,  so  as  to 
augment  the  power  of  the  blow.  A  metal  spring  may 
be  used  in  the  place  of  a  wooden  one. 

f  Figs.  55  and  56.  Table  with  rollers,  p;  its  feet  rest 
on  iron  rails. 


Fig.  55. 


r.  Wheels,  adapted  to  the  feet  of  the  table  and  run¬ 
ning  upon  the  rails.  The  skins  to  be  beaten  are  placed 


BEATING  AND  ROLLING  BY  MACHINERY. 


225 


on  this  table,  and  upon  its  middle  the  anvil,  upon  which 
the  hammer  descends,  is  supported. 


Fig.  56. 


The  anvil  is  chambered  for  the  passage  of  a  current 
of  steam,  for  the  purpose  of  warming  the  copper  face,  y ; 
and  it  rests  upon  springs,  which  are  intended  to  render 
the  shock  of  the  hammer  less  severe,  and  to  diminish 
the  jarring. 

As  the  system  of  vertical  hammers  has  long  been  in 
common  use,  the  invention  of  Flotard  and  Delbut  con¬ 
sists,  really,  only  in  the  use  of — 

1.  The  spring,  for  increasing  the  force  of  the  blow. 

2.  The  check,  for  diminishing  it. 

3.  The  cups,  for  receiving  the  oil  drippings. 

4.  The  movable  table,  with  rollers. 

5.  The  arrangement  of  springs  under  the  face  of  the 
anvil;  and 

6.  In  the  passage  of  vapor. 

M.  Berendorf’s  Machine  for  Pressing  Hides. — The  fol¬ 
lowing  report  upon  and  description  of  this  machine  is 
from  the  Bulletin  of  the  Society  for  Encouragement  of 
Arts,  &c.,  of  the  year  1845,  p.  68: — 

“The  necessity  of  hammering  by  hand  skins  intended 
for  sole-leather,  formerly  a  very  essential  though  fa¬ 
tiguing  means  of  compressing  them,  has  now  been  almost 
entirely  prevented  by  methods  which  much  more  effect¬ 
ually  answer  the  same  purposes.  Among  these  means 
that  of  M.  Berendorf,  which  substitutes  for  hammering 
a  rapidly  applied  compression,  somewhat  analogous  to  it 
in  operation,  has  been  very  successful. 

“The  peculiarity  of  the  mode  employed  by  him  in  the 
use  of  the  machine  invented  in  1844,  consists  not  so 
15 


226 


TANNING. 


much  in  this  substitution  of  rapid  compression  for  ham¬ 
mering,  as  in  the  peculiar  arrangement  of  the  support 
for  the  leather,  which,  by  its  elasticity,  makes  it  possible 
to  confine  the  amount  of  pressure  to  any  desired  limits. 
The  support  is  an  anvil,  resting  upon  a  spring  composed 
of  hard  wood,  the  amount  of  resistance  of  which  can  be 
modified  at  pleasure  by  the  workman,  who,  holding  the 
hide  by  one  hand,  turns  with  the  other  a  screw  which 
exactly  regulates  the  pressure  to  which  any  particular 
part  of  the  leather  may  be  exposed. 

“  The  machine  of  Berendorf  is  powerful,  and  simple 
in  all  its  parts.  A  beam  acts  upon  a  lever,  the  fixed 
point  of  which  is  attached  to  a  cast-iron  support,  which 
forms  the  top  of  a  frame  large  enough  to  receive  a  great 
number  of  hides,  and  having  in  its  middle  an  opening 
through  which  the  piston  which  produces  the  compres¬ 
sion  by  means  of  a  lever  about  to  be  described,  slides. 

“The  compressing  surfaces  in  contact  with  the  hides, 
are  made  of  brass,  are  smooth,  convex,  circular,  and  have 
a  diameter  of  from  3^0  th  to  d^th  inches.  The  skins 
exposed  to  their  action  are  beautifully  smoothed  and 
perfectly  compressed  by  it. 

“The  advantages  of  this  process  in  improving  the 
quality  and  appearance  of  leather,  and  its  superior  cheap¬ 
ness,  have  induced  the  council  to  bestow  upon  M.  Beren¬ 
dorf  a  silver  medal,  and  to  insert  in  their  Bulletin  this 
report,  accompanied  by  a  description  and  plate.” 

This  machine  is  composed,  1st,  of  a  movable  vertical 
hammer,  which  exerts  pressure  upon  the  hides,  2d.  Of 
a  fixed  anvil  upon  which  they  are  placed.  3d.  Of  a 
lever  which  gives  the  impulse  to  the  hammer. 

Fig.  57  exhibits  a  front  view  of  this  machine. 

Fig.  58.  A  plan. 

Fig.  59.  Vertical  and  cross  section,  made  upon  the 
line  a,  b,  in  the  first  figure. 

The  same  letters  apply  to  all  the  figures. 

1.  The  wrought-iron  hammer,  A,  is  furnished  at  its 
inferior  extremity  with  a  face  of  bronze,  and  its  cylin¬ 
drical  shank  or  helve  passes  through  a  vertical  socket  in 
the  large  and  strong  cast-iron  beam  B.  This  latter, 


BEATING  AND  ROLLING  BY  MACHINERY. 


227 


which  is  represented  in  cross  section  by  Fig.  60  (upon 
the  line  C  D,  Fig.  57),  is  strengthened  by  mouldings, 
and  rests,  by  its  extremities,  upon  two  cast  upright 
columns  C  C ,  with  which  it  is  firmly  connected.  The 
space  between  those  uprights,  amounting  to  but  78 
inches,  only  admits  half  hides,  although  M.  Berendorf 
has  also  adopted  another  arrangement  represented  in 
Fig.  61,  which  admits  of  acting  upon  whole  ones.  About 
the  middle  of  the  upper  part  of  the  beam  B ,  an$  near 


228 


TANNING. 


Fig.  59. 


Fig.  60. 


£ 


Fig.  61. 


the  socket,  is  a  projection  D,  which  supports  the  end  of 
the  lever  that  transmits  its  action  to  the  hammer. 

2.  The  anvil  which  receives  the  leather  to  be  com¬ 
pressed,  is  composed  of  an  iron  cylinder  E,  having  a 
brass  face  a\  like  that  of  the  hammer,  and  between  these 
two  the  leather  is  pressed  when  the  latter  descends. 

The  cylinder  passes  freely  through  the  socket  of  the 
large  cross-piece  F,  and  rests  upon  an  elastic  support, 
which  allows  it  to  descend  a  little  under  heavy  pressure, 
and  to  rise  again  rapidly.  This  support  consists  of  a 
thick  wooden  plank  G,  20  inches  square,  fixed  at  its  ends 
to  the  lateral  projections  c,  which  descend  to  the  foot  of 
the  columns  with  which  they  are  connected.  This  piece 


BEATING  AND  ROLLING  BY  MACHINERY. 


229 


of  wood- work  is  so  large  that  it  often  has  to  be  made  of 
two  pieces  bound  together  by  screws  with  nuts  d.  The 
cylinder  does  not  rest  directly  upon  this  wood,  but  upon 
a  steeled  gudgeon,  or  pin,  Fig,  62 ,f.  The  gudgeon  or 
pin  is  threaded  for  part  of  its  length,  and  traverses  a 
copper  nut  g,  sunk  in  a  cast-iron  rim  h,  which  is  let  into 
the  centre  of  the  wooden  support.  By  turning  this  pin 
to  the  right  or  left,  the  cylinder  and  the  anvil  face  a'  are 
made  to  rise  or  fall  along  with  it.  To  effect  this  move¬ 
ment,  the  workman  grasps  a  little  fly  H,  the  axle  of 
which  has  an  endless  screw  which  works  a  toothed-wheel 
I ,  mounted  upon  the  gudgeon.  The  fly  is  turned  more 
or  less,  as  the  thicker  or  thinner  parts  of  the  leather  are 
being  exposed  to  pressure. 

The  leather  placed  between  the  anvil  and  hammer  is 
thus  pressed  to  any  desired  extent,  and,  the  wood  below 
being  elastic,  bends  or  gives  to  some  extent,  and  again 
rebounds  to  its  original  position. 

The  cast  cross-piece  F  which  guides  the  anvil  rests  at 
its  two  ends  upon  the  projections  i  i  of  the  columns  C  C, 
and  upon  each  side  of  it  is  placed  a  table  J,  upon  which 
the  workman  moves  the  hide  in  every  direction,  so  that 
it  may  be  touched  at  all  points  successively. 

3.  The  lever  which  acts  on  the  hammer.  The  head 
of  the  hammer  A  incloses  a  steel  block,  upon  which  a 
prop  j  pivots,  which  is  of  ovoid  form  and  well-tempered 
steel  (Fig.  59);  and  upon  this  prop  the  large  lever  K , 
moving  upon  the  axis  k,  Fig.  63,  is  supported.  When 
it  descends,  it  rests  upon  the  prop  j,  which  oscillates  a 
little  upon  its  centre,  and  forces  down  the  hammer  in  a 
vertical  direction,  and,  in  order  that  it  may  rise  again 
with  it,  they  are  connected  together  by  two  iron  bars, 
terminated  by  arms,  which  are  attached  on  one  side  by 
the  bolt  m,  which  passes  through  the  lever,  and  on  the 
other  by  a  similar  bolt  n,  which  goes  through  the  head 
of  the  hammer  (Fig.  59).  The  play  given  to  these  arms 
is  regulated  by  small  compressing  screws  above  them. 

The  steel  axis  k,  upon  which  the  lever  moves,  rests 
upon  the  upper  part  of  the  projection  D.  A  steel  ring, 
traversed  by  the  axis  k,  is  adjusted  upon  the  centre  of 


230 


TANNING. 


the  lever-head,  and  can  be  easily  replaced  when  worn 
out.  In  order  to  retain  this  axle  in  place,  it  is  covered 
on  each  side  of  the  lever  by  two  strong  stays,  the 
branches  of  which  extend  to  the  top  of  the  beam,  as  well 
as  to  the  projection  D ,  and  are  kept  in  place  by  strong 
nuts. 

M.  Berendorf  moves  his  machinery  by  a  small  oscil¬ 
lating  cylinder  engine,  the  power  being  transmitted  to 
the  lever  K  by  the  two  beams  L  L ,  joined  together  by 
the  double  crank  M.  The  vapor  enters  the  conical 
box  Q,  from  the  boiler  through  the  pipe  s,  raises  the 
piston,  and  escapes  by  the  pipe  t.  The  fly  _R  turns  the 
small  crank  z,  and  works  the  feeding  pump  S,  which  is 
plunged  in  the  reservoir  T.  The  water  is  returned  into 
the  boiler  by  the  tube  a",  when  the  cock  b'  is  open,  and 
a  ball-cock  keeps  up  the  communication  between  a 
reservoir  above  and  the  one  below. 

This  machine  works  ordinarily  at  the  rate  of  140 
revolutions  in  the  minute,  during  which  time  more  than 
a  square  yard  of  surface  is  compressed  by  it.  In  M. 
Berendorf’s  establishment,  where  a  number  of  machines 
are  constantly  working,  from  70  to  80  half-skins  are 
pressed  by  each  apparatus  in  twelve  hours. 

Berenger  and  Co.  have  three  mill-hammers  at  work, 
at  the  rate  of  100  blows  a  minute,  each  one  turning  out 
from  35  to  40  whole  skins  in  a  day. 

M.  Berendorf  has  taken  out  a  patent  of  fifteen  years’ 
duration,  dating  the  7th  of  October,  1842,  and,  still 
later,  two  additional  ones  of  improvements  upon  this  in¬ 
teresting  machine,  which  is  now  completely  established 
in  favor. 

Cox’s  Machine. — A  more  modern  method  of  render¬ 
ing  leather  smooth  and  compact  is  by  passing  it  between 
rollers.  This  mechanical  arrangement,  being  free  from 
tremulous  motions,  and  easily  adjusted  to  any  desired 
rapidity  of  action,  produces  a  uniform  and  powerful 
compression  throughout  the  side  of  leather,  without 
any  liability  of  damaging  it,  as  is  the  case  in  machine 
beatincj. 

Cox  has  invented  a  rolling  mill  in  which  the  roller  is 


BEATING  AND  ROLLING  BY  MACHINERY. 


231 


fixed  at  the  end  of  a  lever,  which,  being  suspended, 
oscillates  like  the  balance  of  a  pendulum. 

This  roller,  made  of  copper  or  brass,  5  inches  in  diam- 
ter  and  9  inches  in  length,  is  suspended  by  its  axes  in 
the  chaped  end  of  an  iron  lever  6  inches  in  diameter 
and  11  feet  10  inches  long.  The  upper  end  of  this 
lever,  also  terminating  in  a  chape,  is  movable  upon 
pivots  attached  to  a  beam  or  block  15  feet  long  and  2 
feet  wide.  This  beam  is  free  at  its  anterior  extremity, 
and  is  so  jointed  at  the  other  as  to  enable  it  to  move 
upwards  and  downwards,  and  it  rests  on  each  side  upon 
two  supports  placed  below  it.  The  weight  is  in  a  box 
resting  upon  the  body  of  the  lever,  which  is  moved  by 
the  aid  of  a  crank  attached  to  it  at  a  distance  of  rather 
less  than  two  feet  above  the  roller.  The  lever  should 
move  through  a  space  of  3  feet  8  inches,  but  this  can 


Fig.  64.  Fig.  65. 


be  increased  or  diminished.  The  copper  or  brass  sup¬ 
port  is  hollowed  out,  so  that  the  roller  can  pass  along 
its  whole  extent,  and  reach  all  parts  of  the  leather.  As 
soon  as  the  hide  is  placed  upon  this  support,  the  block 
or  beam  is  made  to  rise,  and  the  whole  weight  bears 
directly  upon  the  leather.  At  the  end  of  its  course, 


232 


TANNING. 


where  the  support  is  flat,  the  roller  is  raised  up  by  the 
beam,  the  weight  is  borne  down  again  upon  the  leather 
when  it  reaches  the  middle,  and  is  again  elevated  by  the 
supports  placed  under  the  beam. 

Fig.  64  is  a  front  view,  and  Fig.  65  a  side  view,  of 
this  machine.  P,  beam,  movable  at  its  hind  end  by  a 
hinge  C  fixed  in  the  wall  (Fig.  66),  and  maintained  in 
a  horizontal  position  at  the  other  end  by  the  supports 
B  B.  P,  lever  joined  to  the  beam  Pby  the 
Fig.  66.  pivots  $  S,  and  terminated  by  a  fork  M 

r  which  holds  the  roller  P,  running  over  the 

3  curve  A.  This  curve  has,  at  either  end,  a 
plane  surface  E,  where  the  roller  leaves  it 
and  is  raised  up  by  the  pivots  S.  D  is  the  horizontal 
shaft  connected  with  a  crank  which  moves  the  lever  P, 
and  G  is  a  box  containing  a  weight  heavy  enough  to 
cause  the  necessary  pressure  at  the  moment  when  the 
roller  reaches  the  plane  end  of  support. 

Wiltse's  Rolling  Table. — This  machine,  somewhat  sim¬ 
ilar  in  construction  to  the  preceding,  is  shown  by  the 
accompanying  drawing,  Fig.  67,  made  to  a  scale  of  the 


IK 


Fig.  67. 


eighth  of  an  inch  to  a  foot.  The  machine  consists  of  a 
spring  pole,  a  lever  6,  to  which  the  head  of  the  vibrator 
d  is  attached,  and  which  is  rendered  compound  by  a 


BEATING  AND  ROLLING  BY  MACHINERY.  233 

connection  with  a  second  lever  c.  This  combination 
acts  through  the  vibrator  d  upon  the  roller  <7,  and  is 
propelled  by  the  foot  working  the  treadle  e  e.  The  bed 
h  is  of  lignum-vitae  wood,  and  the  table  i,  upon  which 
the  leather  is  spread  while  being  gradually  drawn  under 
the  roller,  is  8  feet  wide  and  16  long.  The  bed  is  the 
part  upon  which  the  leather  is  rolled,  and  is  firmly  sup¬ 
ported  by  a  heavy  log  /,  which,  in  its  turn,  rests  se¬ 
curely  upon  the  supports  o  o  o  o  and  the  sill  n  of  the 
building.  The  connection  f  with  the  balance-wheel  b 
forms  a  crank  by  which  a  vibrating  motion  is  commu¬ 
nicated  to  d.  The  pulley  m  on  the  same  shaft  is  the 
driving  medium,  and  the  roller  should  move  at  the  rate 
of  130  revolutions  a  minute. 

Fig.  68  is  a  view  of  the  rollers  A  A,  one  of  which  is 


Fig.  68. 


represented  as  it  is  retained  in  working  position  by  the 
straps  B  B,  and  the  other  detached.  A  side  view  of 


234 


TANNING. 


the  strap  is  also  given  in  a  separate  figure  B.  The 
wrench  C  is  used  for  turning  the  nuts  E.  The  lips  F 
F  are  oil-holes  for  lubricating  the  journals  of  the  roller. 

The  roller  is  made  of  a  composition  of  copper  and 
tin,  with  a  steel  shaft  penetrating  through  it. 

These  mills  and  appliances  are  made  in  a  creditable 
style  of  art  by  Wiltse  and  Co.,  Catskill,  New  York. 

Seguin’’ s  Machine  to  Flesh  and  Gloss  Leather. — This 
machine  is  composed  of  two  metallic  rollers  six  feet 
long ;  one  carries  a  sharp  blade,  spiral  in  form,  and  is 
destined  to  flesh  the  skin  enveloped  on  another  roller 
21  feet  in  diameter,  while  the  first  is  but  six  inches. 
On  the  circumference  of  the  lower  roller  and  parallel 
to  its  axis  a  groove  is  made  in  which  the  end  of  the 
leather,  maintained  by  hooks,  is  engaged ;  the  sharp 
blade  is  thus  disposed  to  form  from  the  centre  of  the 
roller  a  spiral  which  makes  a  full  turn  to  the  two  ends. 
The  pivots  of  the  rollers  turn  those  of  the  lower  roller 
in  fixed  steps,  and  those  of  the  upper  roller  in  true 
levels  by  which  they  raise  or  lower  this  last  roller  to 
make  it  stand  on  the  large  roller.  The  movement  of 
these  rollers  turning  in  opposite  directions  is  combined 
so,  that  when  the  upper  roller  makes  a  full  revolution,  the 
lower  one  advances  only  one-twelfth  of  its  circumference. 
The  pressure  of  the  upper  roller  on  the  leather  can  be 
regulated  by  loading  the  levels  with  weights,  more  or 
less  heavy,  the  leather,  being  engaged  by  the  end  in  the 
groove  of  the  lower  roller,  rolls  around  this  roller  as 
soon  as  it  turns. 

At  that  moment  they  put  the  sharp  blade  of  the  lower 
roller  in  operation,  so  that  the  skin  is  fleshed  from  the 
centre  to  the  ends  on  all  its  length. 

CHAPTER  XLIII. 

TISSUE  AND  QUALITY  OF  LEATHERS— THEIR  DEFECTS 
AND  THE  WAY  OF  ASCERTAINING  THEM. 

We  have  made  known  the  composition  and  structure 
of  the  skin ;  it  is  then  evident  that  well-tanned  leather 


TISSUE  AND  QUALITY  OF  LEATHER. 


235 


ought  to  form  a  homogeneous  body  from  which  it  is  im¬ 
possible  to  extract  fibrin  and  gelatine.  These  principles 
are  in  a  state  of  perfect  combination,  and  while  the 
fibrous  tissue  is  not  destroyed,  it  is,  however,  reduced  to 
such  a  state  that  it  is  not  fibrin.  According  to  what  we 
have  indicated  before,  it  is  evident  that  if  barks  of  good 
quality  have  been  used,  if  the  operation  has  been  well 
conducted,  the  leather  must  be  of  good  quality ;  but  if 
one  or  several  of  these  operations  have  not  been  well 
executed,  and  if  the  barks  are  poor  in  tanning  princi¬ 
ples,  the  leather  presents  imperfections  which  diminish 
its  quality.  It  is  ordinarily  by  cutting  that  the  quality 
of  leather  is  ascertained;  that  well  manufactured  pre¬ 
senting  a  bright  cut  and  a  hard  body.  It  is  everywhere, 
except  on  the  hair  side,  of  an  equal  color,  and  the  inside 
has  the  appearance  of  an  open  nutmeg.  The  tail,  the 
back,  and  the  throat  being  the  thickest  and  most  essen¬ 
tial  parts,  are  those  which  are  cut  in  order  to  ascertain 
the  quality  of  the  leather. 

You  can  judge  a  leather  is  badly  manufactured  or  im¬ 
paired  when  its  edge  is  yellowish  or  blackish,  when  you 
perceive  in  the  centre  a  black  or  whitish  line,  and  at 
last  when  its  tissue  is  loose  and  spongy. 

Too  long  a  stay  in  the  vats,  the  vat  being  badly  com¬ 
posed  or  managed,  a  want  of  dampness  in  a  vat  which 
loses  water,  and  other  different  circumstances,  may 
deteriorate  the  leather.  Then  you  perceive  that  it  is 
spongy,  too  open,  wants  weight,  has  not  the  proper  color 
nor  the  requisite  hardness  to  be  good  in  use ;  but  the 
evil  is  without  remedy,  and  the  quality  cannot  be  re¬ 
stored.  Generally  the  outside  color  of  leather  depends 
on  the  manner  in  which  it  has  been  swelled  and  tanned. 
The  leather  swelled  with  lime  is  nearly  black  on  the 
hair  side,  and  red  on  the  flesh  side,  the  inside  is  light 
red ;  the  color  of  leather  raised  with  barley  is  slatish  on 
the  hair  side,  and  whitish  on  the  flesh  side  and  the  edge. 
That  with  garouille  bark  is  of  a  blackish-brown,  and  has 
a  strong  and  disagreeable  odor  that  it  always  keeps, 
while  leather  tanned  with  birch  has  an  agreeable  odor. 

It  is  impossible  to  tan  perfectly  the  thin,  hollow, 


236 


TANNING. 


and  dry  skins,  those  which  are  difficult  to  swell,  or  those 
which  do  not  swell  in  a  satisfactory  manner. 

It  is  also  difficult  to  prepare  well  skins  which  are  full 
of  cuts,  and  those  from  Ireland,  and  Brazil.  Skins  put 
into  muddy  waters  are  often  pricked;  there  are  some 
others  so  difficult  to  depilate,  that  there  remain  on  the 
side  foreign  substances,  thus  explaining  the  reason  why 
in  working  on  the  beam  they  are  cut,  because  those 
parts  which  are  hard  resist  the  knife. 

When  the  skins  have  remained  too  long  in  the  lime, 
sometimes  they  are  burned  in  such  a  way  that,  by  taking 
them  with  the  nippers,  they  are  torn,  and  it  is  nearly 
impossible  to  flesh  them.  It  is  a  fact  beyond  question 
that  a  fresh,  clear,  and  pure  water  is  the  only  one  proper 
for  the  preparation  of  leather. 

Leather  is  called  horny  when  some  parts  of  it  are 
dried  and  hard  as  horn,  because,  not  having  been  soft¬ 
ened,  the  tan  has  not  penetrated  them.  To  obviate  this 
defect,  you  must  be  careful  not  to  leave  them  in  the 
open  air. 

Some  leathers  contain  a  multitude  of  small  holes ; 
these  holes  deteriorate  the  leather  to  such  an  extent 
that  it  lets  in  water.  A  good  plan  to  test  the  quality 
of  a  leather  is  to  put  into  water  a  piece  previously 
weighed,  and  leave  it  in  for  a  few  days.  If,  when  with¬ 
drawn,  this  leather  has  acquired  a  considerable  weight 
in  proportion  to  its  volume,  it  is  a  sure  sign  that  it  is 
spongy,  and  consequently  badly  tanned.  If,  on  the  con¬ 
trary,  its  weight  is  nearly  the  same  as  before,  the  leather 
is  of  good  quality ;  consequently  the  more  dampness  a 
leather  absorbs  the  more  spongy  it  is. 

Leather  kept  more  than  two  years  does  not  improve- 
in  quality.  It  dries  and  diminishes  in  weight,  which 
is  a  loss  to  the  manufacturer,  who  should  keep  it  in  a 
damp  store. 

Action  of  Frost  on  Leather.  —  Many  inquiries  have 
been  made  for  the  purpose  of  ascertaining  whether  the 
freezing  of  leather  will  add  to  its  weight.  We  answer 
no,  quite  the  contrary.  The  particles  of  water  freeze 


TISSUE  AND  QUALITY  OF  LEATHER. 


237 


within  the  pores  of  the  leather  and  become  expanded, 
and  to  that  extent  that  the  sides  appear  bloated.  But 
when  the  icy  particles  melt  away,  the  side  is  left  in  a 
spongy,  softened  state,  which  very  much  injures  the  fibre 
of  the  leather,  and  to  some  extent  takes  from  the  weight 
of  the  side.  We  are  not  unaware  thctt  some  tanners 
infer,  because  they  get  a  larger  gain  in  weight  in  Avin- 
ter  than  in  summer,  that  this  gain  is  in  some  way  the 
result  of  frost;  but  this  fact  is  attributable  to  other 
agencies,  which  we  will  not  consider  at  this  time. 

The  influence  of  frost  upon  color  is  very  marked,  and 
is  attributed  to  a  chemical  change,  and  it  is  a  fact  that 
leather  frozen  dry  will  be  many  shades  lighter  in  color 
than  if  dried  by  any  artificial  heat.  It  is  also  true  that 
leather  thus  dried  is  much  softer,  but  then  this  is  clearly 
attributable  to  the  heaving  of  the  fibre  by  the  frost.  It 
is  a  sad  mistake  to  suppose  that  frost  adds  either  to  the 
weight  or  quality  of  leather.  The  only  good  it  can 
accomplish  is  on  short  tanned  or  crusty  hard  leather,  it 
directly  tends  to  overcome  those  difficulties ;  but  upper 
leather  and  calf  frozen  dry  will  always  cut  a  flesh  more 
open  and  coarse  than  when  dried  by  the  natural  air 
Avithout  freezing.  We  do  not  allude  to  this  subject  just 
noAv  so  much  to  correct  errors  on  this  point,  as  to  suggest 
that  the  Avhole  subject  of  drying  leather  should  receive 
more  attention.  Suppose  it  can  be  demonstrated  that 
sole-leather  can  be  dried  in  forty-eight  hours  Avithout 
injury  either  to  the  Aveight  or  color,  how  valuable  Avould 
such  an  improvement  be.  Under  such  circumstances 
no  tanner  would  require  more  than  1000  to  1500  sides 
exposed  at  any  one  time,  besides  saving  the  interest  for 
at  least  one  month  on  his  Avhole  stock. 

It  is  believed  that  steam,  when  properly  applied,  can 
accomplish  this  result,  and  it  has  been  done,  as  we  shall 
see  hereafter. 


238 


TANNING. 


CHAPTER  XLIV. 

BELT  LEATHER. 

The  name  of  belt  or  crop  leather  is  applied  to  leather 
made  from  the  skins  of  cows  or  small  oxen,  provided 
they  possess  sufficient  thickness,  as  their  tissue  is  more 
compact  than  that  of  ox-hides,  at  least  if  the  cows  have 
not  already  calved.  The  skins  of  young  oxen  are  defi¬ 
cient  in  thickness  and  firmness,  and  are  only  used  for 
conversion  into  belt  leather. 

This  kind  requires  a  much  more  thorough  currying 
than  thick  hides,  which  are  almost  fit  for  use  when 
taken  from  the  tanning.  It  is  employed  principally  by 
shoemakers  for  second  soles  and  uppers  for  women’s 
shoes  and  men’s  light  shoes  and  pumps.  Young  ox-hides 
are  regarded  by  shoemakers  as  inferior  to  cow-hides; 
and  they  use  the  latter  for  upper  and  thin  soles.  The 
tanning  of  these  hides  is  conducted  in  a  somewhat  dif¬ 
ferent  way  from  that  of  thick  hides. 

At  first  they  are  placed  in  the  lime-pits;  and  when 
ready  for  depilation,  which  is  generally  in  eight  days 
during  summer,  and  ten  or  twelve  in  winter,  are  repeat¬ 
edly  fleshed  and  scraped,  care  being  taken  to  rinse  them 
each  time  in  clean  and  running  water,  if  possible,  so  as 
to  remove  all  the  lime.  Those  intended  for  uppers  re¬ 
quire  at  least  four  or  five  rinsings,  while  two  will  suffice 
for  those  which  are  to  be  used  as  soles.  They  are  then 
deposited  in  wooden  vats,  feet  in  height  and  6|  feet 
wide,  which  are  nearly  two-thirds  filled  with  weak  in¬ 
fusion  of  oak  bark,  and  are  handled  daily. 

If  the  hides  are  worked  in  the  same  vat,  the  strength 
of  the  infusion  must  be  restored  as  rapidly  as  exhausted 
by  fresh  additions  of  bark. 

When  transferred  to  other  vats,  the  liquor  must  be 
made  successively  and  successively  stronger.  Usually, 
tanners  prefer  this  method ;  but  sometimes  skins  are 
treated  in  hot  infusions,  prepared  in  vats  similar  to  those 
just  described,  by  adding  hot  water  to  bark  in  the  pro- 


BELT  LEATHER. 


239 


.  % 

portion  of  five  baskets  for  every  twenty-four  cow-skins. 
After  being  placed  in  the  vats,  the  skins  are  repeatedly 
handled  or  moved  about  by  the  workmen.  This  work¬ 
ing  is  frequently  repeated,  the  skins  being  taken  out 
daily  to  drain;  and  a  little  fresh  bark  being  added  to 
the  vats  in  the  interval.  This  manipulation  is  continued 
from  four  to  six  weeks.  The  following  figure  represents 
the  operation. 

Fig.  69. 


Whichever  of  these  methods  is  adopted,  the  hides  are 
next  subjected  to  a  mixture  of  ground  bark  and  strong 
liquor  in  other  vats.  For  this  purpose  the  bottom  of 
the  vat  is  covered  with  a  layer  of  fresh  tan,  carefully 
moistened,  upon  which  a  skin  is  spread  out  to  its  full 
extent ;  this  is  covered  with  another  layer  of  tan,  and 
the  hides  and  bark  are  alternately  packed  in  till  the  vat 
is  full.  The  top  hide  must  have  a  “  hat”  of  bark,  and  the 
contents  of  the  vat  be  then  drenched  with  the  solution. 

The  workman  should  be  careful  to  place  the  skins  in 
every  direction  around  the  pit,  the  end  of  the  contiguous 
ones  forming  slight  angles  with  each  other,  and  to  de¬ 
posit  tan  in  all  the  creases  and  doubling  made  by  the 
bending  of  the  edges.  This  process  usually  requires  six 
weeks.  Five  baskets  of  tan  are  used  for  a  dozen  ordi¬ 
nary  cow-skins,  and  about  six  for  six  dozen  young  ox¬ 
hides.  The  skins,  having  undergone  this  preparation, 
are  then  further  exposed  to  two  treatments  in  the  vats 
in  precisely  the  same  manner.  After  remaining  in  the 
first  pit  for  three  months,  they  are  taken  out,  and,  before 


240 


TANNING. 


being  transferred  to  the  second  one,  are  beaten  or  trod 
out  for  the  purpose  of  rendering  them  more  supple. 
This  process  having  been  completed,  they  are  placed  in 
the  second  and  last  pit.  Some  tanners  are  satisfied  with 
five  weeks’  exposure  in  this  last  pit;  some  others  extend 
the  time  to  three  months.  This  latter  period  is  not  too 
long  for  leather  of  good  quality.  After  withdrawing, 
the  leather  is  dried  in  the  usual  manner,  being  careful 
not  to  expose  it  to  the  sun,  a  strong  wind,  or  a  cool  or 
damp  atmosphere,  in  which  it  might  mould;  then  it  is 
transferred  to  the  currier,  who  prepares  it  according  to 
the  kind  and  quality  of  the  leather  required. 

Cow-skins  differ  much  in  quality,  those  of  the  younger 
animals  being  much  superior  to  those  of  cows  which 
have  frequently  calved;  the  latter  having  become  weak 
and  thin  by  the  distension  to  which  they  have  been  sub¬ 
jected.  Young  ox-skins  also,  long  regarded  as  inferior 
to  the  latter  kind  of  cow-skins,  are  equally  serviceable; 
and  the  shoemakers  now  use  them  indifferently. 

The  above  process  is  employed  in  the  best  establish¬ 
ments  of  Paris;  but,  in  the  provinces,  some  tanners  vary 
it  more  or  less. 

In  Brittany  this  leather  is  made  by  the  process  of  tan¬ 
ning  in  sacks.  After  having  been  exposed  in  the  lime 
pits  for  two  months,  and  placed  for  eight  days  in  hot 
ooze  and  water,  they  are  then  filled  with  the  decoction, 
and  left  for  a  week  or  more,  being  careful  to  change  their 
position  five  or  six  times  a  day.  Then  they  are  un¬ 
ripped,  placed  between  layers  of  bark,  and  allowed  to 
remain  untouched  during  eight  days  before  being  finally 
taken  out  and  dried. 

In  Limousin  they  are  lined  for  four  days,  then  placed 
in  the  tan  pits,  in  which  they  are  allowed  to  remain  for 
three  months. 

In  Dauphine  they  are  limed  for  fifteen  days,  then 
exposed  for  four  weeks  to  two  different  treatments  with 
barks,  and  transferred  to  the  vats,  where  they  remain 
for  a  month  and  a  half. 

At  Metz  and  Verdun,  after  having  lain  for  eight  days 
in  old  lime  pits,  and  as  much  longer  in  fresh  ones,  they 


BELT  LEATHER. 


241 


are  exposed  to  the  action  of  ooze  for  one  month,  and 
afterwards  to  two  stratifications  with  tan  for  five  months 
longer. 

At  Bourges  and  in  different  places  in  Berry  they  are 
allowed  to  remain  three  months  in  the  lime  pits  and 
six  months  in  the  tan  vats. 

At  St.  Germain,  cow  and  calf-skins  are  passed  through 
three  old  lime  pits  and  one  fresh  one,  and  then  undergo 
five  cleanings  and  rinsings.  They  are  then  beamed  and 
relieved  with  the  knife  of  all  superfluities,  and  worked 
upon  the  hair  side  with  a  whetstone,  and  when  thus 
well  softened  and  clean,  are  again  thrown  into  the  water. 
After  being  worked  for  the  third  time  upon  the  horse 
with  the  round  knife  on  both  sides,  so  as  to  expel  the 
last  portion  of  lime,  they  are  again  rinsed ;  and  a  fourth 
and  fifth  time  treated  in  the  same  way.  The  final  rinse 
water  should  come  from  them  perfectly  clear,  aftd  leave 
them  in  a  proper  state  for  the  ooze  bath. 

How  to  Manufacture  Cow-leather  into  Uppers  of  a  su¬ 
perior  quality. — In  order  to  be  good,  upper  leather 
should  have  the  following  properties: — 

1st,  the  pores  should  be  very  close,  constituting  its 
solidity.  2d,  the  leather  should  remain  pliant  and  not 
break  easily  in  use.  3d,  the  leather  should  be  water¬ 
proof,  so  that  the  feet  may  be  kept  dry  in  the  dampest 
weather. 

The  following  instructions  should  be  observed  in  manu 
facturing  cow  leather  uppers  possessing  the  above 
named  properties.  In  choosing  the  hides  such  skins 
only  should  be  selected  as  are  of  light  weight,  and  whose 
exterior  promises  leather  of  a  superior  quality.  In  the 
selection,  attention  should  be  given  above  all  things  to 
the  hair;  if  it  is  fine  and  glossy,  it  is  an  evidence  that 
the  animal  was  well  fed.  The  next  point  is  the  horns; 
if  they  are  short  and  sharp  pointed,  then  the  animal  was 
young.  With  regard  to  the  flesh  side,  it  should  be  as 
even  as  glass  and  devoid  of  the  bites  of  cattle  worms. 
If  otherwise  the  skins  are  free  and  thin,  they  may  be 
considered  in  a  suitable  condition  to  be  transformed  into 
fine  upper  leather. 

16 


242 


TANNING. 


In  places  where  this  sort  of  cow-skins  accumulate, 
it  is  advisable  to  work  them  while  they  are  still  fresh. 
It  is  true  that  it  is  necessary  to  pare  them  before  putting 
them  in  water,  still  the  drying  operation  is  gained  by 
this,  and  the  leather  made  from  them  is  as  good  and 
even  more  heavy  than  that  produced  from  milled  hides. 

But  as  the  tanner  does  not  receive  many  fresh  hides, 
he  is  obliged  either  to  buy  dry  hides  or  to  have  them 
dried  himself.  In  the  drying  operation  great  care  must 
he  taken,  especially  in  summer  and  autumn,  that  the 
hides  while  suspended  on  poles  do  not  rot  and  lose  their 
hair,  which  unfortunately  happens  very  often. 

In  order  to  avoid  rotten  spots,  Mr.  V.  Mathesias  pro¬ 
ceeds  as  follows :  When  the  hide  is  laid  on  the  table, 
first  remove  all  the  fat,  then  stretch  it  well  out,  and 
sprinkle  it  with  about  one  pound  of  salt,  and  as  soon  as 
it  has  been  rubbed  in  hang  the  hide  up.  It  is  not  then 
necessary  to  stretch  it  so  carefully.  Thus,  this  ad¬ 
vantage  is  gained,  that  the  hides  being  dry,  they  are 
seldom  attacked  by  moths  or  worms.  Another  advan¬ 
tage  is,  that  they  are  much  easier  to  refreshen  than 
hides  which  are  not  salted.  In  my  opinion,  there  is  no 
need  to  give  heed  to  the  fresh,  especially  when  one  is 
able  to  use  block  salt. 

It  is  not  advisable  to  put  more  than  from  twenty  to 
twenty-four  hides  into  the  water  at  a  time,  even  where 
upper  leather  tanning  is  carried  on  on  a  large  scale  ; 
still,  in  the  spring  the  number  may  be  doubled,  for  the 
reason  that  the  vats  can  be  filled  at  several  stages. 

The  first  day,  the  skins  to  be  refreshened  should  be 
hung  in  running  water ;  and  in  places  where  this  is  not 
practicable,  stretch  them  out,  and  pour  water  upon  them 
time  and  time  again. 

After  the  hides  have  become  softened  by  this  opera¬ 
tion,  they  should  be  placed  in  the  vat,  and,  if  possible, 
add  spring  water  until  the  hides  are  entirely  submerged. 
The  next  day  raise  them,  and  put  them  back.  This  is 
necessary  to  make  the  tanning  uniform.  The  fourth 
day  raise  them  again.  This  should  be  done  often  if  the 
weather  be  warm,  and  also  if  the  water  in  which  the 


BELT  LEATHER. 


243 


hides  are  soaked  be  hard ;  then  they  may  be  stretched 
on  the  apparatus  for  that  purpose ;  but,  before  doing 
this,  it  should  be  ascertained  that  they  are  soft  to  the 
touch.  Then  they  are  to  be  cleaned,  in  order  that  they 
may  be  stretched  lengthways  on  the  table,  which  has 
been  previously  covered  with  one  hide. 

When  hides  have  been  salted  before  drying,  or  when 
they  have  not  been  salted  at  all,  provided  that  they 
have  not  been  dried  too  much,  the  stretching  operation 
is  easy  ;  but  there  are  cases,  especially  if  the  skins  have 
been  dried  in  the  sun,  when  this  operation  requires 
much  force,  especially  when  the  skins  known  as  kips  are 
concerned.  After  having  properly  stretched  the  skins, 
they  should  be  put  back  into  the  same  water  from  which 
they  have  been  taken.  The  next  day  raise  them,  and 
examine  whether  they  have  become  well-soaked.  If  you 
find  any  that  do  not  appear  to  give  satisfaction  in  this 
respect,  put  them  back ;  but  if  there  are  any  that  are 
still  very  hard,  these  should  be  stretched  again.  It  is 
absolutely  necessary  that  the  hides  should  be  completely 
refreshened  before  being  placed  in  the  lime  pit.  If  they 
are  placed  in  it  in  a  hard  state  they  will  remain  hard, 
even  after  they  have  become  converted  into  leather. 
Therefore,  we  may  look  upon  the  refreshening  as  the 
first  basis  of  the  tanning  of  pliant  leather. 

East  India  kips,  which  for  many  years  past  have  been 
tanned  into  upper  leather,  require  a  special  mode  of 
treatment  for  the  freshening.  In  India,  they  are  first 
stretched,  and  dried  by  the  heat  of  the  burning  sun ; 
then,  in  order  to  protect  them  against  worms,  while  they 
remain  in  store  and  during  their  long  voyage,  they  are 
sprinkled  with  lime  or  nitre  dissolved  in  water,  or  with 
arsenic.  They  are,  therefore,  often  very  difficult  to 
soak ;  some  of  them  cannot  even  possibly  be  well  re¬ 
freshened,  as  they  are  half  burned.  This  species  of 
hard  hide  is  tanned  for  the  purpose  of  making  inner 
soles.  At  least,  this  is  the  best  use  to  which  they  can 
be  put. 


244 


TANNING. 


CHAPTER  XL  V. 

TANNING  OF  CALF-SKINS. 

The  tanning  of  calf-skins  is  conducted  much  in  the 
same  way  as  small  cow-hides.  After  being  pressed  to 
expel  oleaginous  matters,  they  are  passed  three  times 
through  old,  and  once  through  fresh  lime- vats ;  but, 
being  too  weak  to  bear  the  full  strength  of  the  lime, 
this  should  be  done  after  the  passage  of  cow-skins 
through  the  vats  has  somewhat  diminished  its  activity. 
If  they  are  dried  when  brought  up  into  the  tannery, 
they  must  be  first  trodden  out  and  soaked.  Then  they 
are  scraped,  carefully  fleshed  and  rinsed,  after  which 
they  are  ready  for  a  part  of  the  process  differing  from 
that  used  for  cow-skins. 

Place  from  fifteen  to  eighteen  skins  in  a  tub,  beat 
them  for  eight  or  ten  minutes.  This  operation  softens 
the  fibre,  and  is  repeated  after  each  rinsing,  but  it  is 
omitted  in  establishments  where  the  skins  are  rinsed  as 
often  as  six  times.  The  beaters  are  wedge-shaped,  from 
to  10  inches  in  diameter. 

The  skins,  being  entirely  free  from  hair  and  lime,  are 
placed  in  the  hot  ooze  and  water,  and  treated  like  cow- 
skins,  excepting  that  they  require  more  frequent  and 
careful  handling.  Be  careful  to  put  fresh  tan  each  time 
into  the  vats.  Submit  them  to  the  action  of  stronger 
ooze,  and  tan  in  the  same  way  as  other  skins  for  a 
month,  when  they  are  afterwards  transferred  to  the  pits. 
In  these  they  are  folded  lengthwise  and  unequally,  and 
thus  spread  over  with  tan,  being  careful  to  cover  the 
heads  and  tails  with  rather  more  tan  than  the  other 
parts.  The  tan  used  should  be  of  the  first  quality. 
They  are  exposed  in  the  first  pit  for  three  months. 
They  are  then  taken  out,  freed  from  all  particles  of  tan 
which  adhere  to  them,  and  placed  in  the  second  pit 
with  tan  which  is  reduced  to  the  finest  state  of  division. 
They  are  folded  double,  and  unevenly  as  before,  but  in 
such  a  manner  that  the  part  before  covered  shall  now 


TANNING  OF  CALF-SKINS. 


245 


be  exposed.  Fill  up  the  pits  as  usual;  moisten  the 
whole  with  warm  water,  and  leave  three  months,  then 
the  skins  are  ready  to  be  curried. 

Some  tanners,  instead  of  using  cold  water  to  moisten 
their  pits  with,  employ  a  warm  infusion  of  bark,  which 
is  an  improvement  upon  the  old  process. 

As  it  is  important  to  have  the  skins  soft  and  ready 
to  absorb  the  tanning  liquor,  some  tanners  remove  all 
traces  of  opposing  substances,  such  as  grease,  lime,  etc., 
with  the  help  of  an  alkaline  lye,  which  consists  of  water 
impregnated  with  pigeon’s  or  hen’s  dung,  and  is  techni¬ 
cally  called  a  bate.  Ten  or  twelve  gallons  are  sufficient 
for  one  hundred  skins  ;  and  during  the  time  they  remain 
in  the  last  liquor — from  eight  to  ten  days — they  are  fre¬ 
quently  handled  and  scraped.  After  the  action  of  the 
bate,  the  skins  assume  the  form  of  pelts,  in  which  state 
they  are  placed  in  the  ooze  vats.  The  bate  acts  by  means 
of  its  hydrochlorate  of  ammonia.  The  lime  in  the  skins 
decomposes  it,  takes  its  acid,  and  becomes  hydrochlorate 
of  lime,  which  is  soluble,  and  carried  away  by  the  wash¬ 
ing  waters,  while  the  ammonia  disengages  in  a  gaseous 
state.  If  the  dung  is  fresh,  the  organic  matter  it  contains 
is  liable  to  putrefy,  which  involves  a  partial  decomposi¬ 
tion  of  the  gelatinous  tissue  and  a  loss,  and  at  the  same 
time  imparts  a  very  disagreeable  odor  to  the  leather. 

CHAPTER  XLVI. 

TANNING  OF  CALF-SKINS  FOR  THE  PREPARATION  OF 
WAXED  CALF-SKINS.  BY  MR.  RENE.1 

I. — Before  entering  into  the  details  of  the  manufac¬ 
ture  of  waxed  calf-skins,  which  within  the  last  thirty 
years  has  attained  to  so  great  an  importance,  we  wish  to 
say  a  few  words  on  the  origin  of  this  specialty,  and  of 
the  time  when  this  kind  of  work  began  to  be  seriously 
developed  in  France. 

About  fifty  years  since,  the  fabrication  of  waxed  calf¬ 
skins  was  scarcely  known  in  France;  only  black-grained, 

1  From  “La  Halle  aux  Cuirs.”  Paris. 


246 


TANNING. 


stamped,  and  white  calf-skins  were  produced.  The  first 
two  articles  were  already  well  made ;  they  alone,  with 
cow-hides  in  oil,  being  used  for  men’s  and  women’s  shoes. 
The  white  skins  were  exported  to  Spain,  Portugal,  Italy, 
Constantinople,  Smyrna,  Alexandria,  Malta,  and  Sicily. 

Let  us  describe  in  a  few  words  how  those  white  calf¬ 
skins  were  prepared.  We  shall  not  at  present  speak  of 
the  method  of  tanning.  We  wish  only  to  make  known 
the  processes  to  which  they  were  subjected  after  tanning, 
in  order  to  prepare  them  to  be  delivered  for  exportation. 

On  being  taken  from  the  pit,  they  were  piled  lightly 
for  drying,  then  scraped,  either  over  a  horse  with  a  tan¬ 
ner’s  knife,  or  on  a  table  with  a  stretching  iron,  but  this 
was  done  very  lightly;  then  they  were  placed  in  oil  of 
a  rather  thin  consistence,  mixed  with  fish  oil.  On  the 
fleshy  side  they  generally  used  fine  degras,  such  as  is 
used  by  chamois  dressers;  they  were  then  hung  up  to 
dry.  The  calf-skins  being  dried  after  lying  some  days 
in  a  pile,  were  folded  muff-like,  and  pressed  on  the 
bickern,  beaten  well  on  the  bench  with  a  cork  club,  then 
turned  again  and  scraped  against  the  grain  with  the 
same,  and  finally  grained  with  a  cork  board  from  the 
four  false  quarters,  and  then  they  were  ready  for  exporta¬ 
tion.  These  calf-skins  presented  a  clumsy  resemblance 
to  the  rough  Milan  skins. 

About  1808  four  Irish  curriers  established  themselves 
in  France.  They  were  expert  workmen,  and  they  brought 
with  them  a  new  branch  for  us  in  the  leather  business, 
and  the  specialty  at  length  placed  French  currying  in 
the  first  rank,  for  it  may  now  be  said  to  be  without  a 
rival  in  this  particular  kind  of  manufacture.  These 
Irish  workmen  formed  apprentices;  and,  after  Paris, 
Pont-Audemer  had  the  first  instructed  workmen.  It 
was  also  through  those  Irishmen  that  we  learned  to 
curry  horse-hides. 

At  that  time  France  was  in  the  middle  of  a  long  war 
with  England,  the  ports  were  blockaded,  and  the  demand 
was  only  for  home  consumption.  Consequently  few 
waxed  calf-skins  were  manufactured,  except  for  large 
cities,  where  they  were  used  for  elegant  shoes.  Waxed 


TANNING  OF  CALF-SKINS. 


247 


calf-skin  was  then  employed  much  as  varnished  calf-skin 
has  been  within  the  last  ten  years,  during  which  the 
fashion  of  wearing  patent  leather  shoes  has  been  com¬ 
mon  in  the  cities,  while  in  smaller  towns  cow-hide  in 
oil  and  grained  calf-skins  formed  the  principal  staple  of 
consumption.  Horse-hide,  when  known,  became  a  rage; 
every  currier  produced  smooth  horse-leather,  until  it 
came  to  be  the  patent  leather  of  the  time.  In  1814  the 
style  of  boot  introduced  by  Russians,  of  white  calf-skin, 
diminished  the  call  for  horse-hide.  We  may  say  at  once 
that  the  English  were  then  far  from  having  reached  the 
perfection  attained  in  our  day  in  the  preparation  of 
upper  leather.  The  waxed  calf-skin  alone  was  finished 
of  about  the  same  quality  as  now,  and  even  better. 

The  fabrication  of  boot-legs,  then,  from  1814,  rapidly 
improved  in  France;  but  waxed  calf-skins,  properly  so 
called,  were  still  in  the  background,  if  not  as  a  manu¬ 
facture,  at  least  as  an  important  article  of  sale. 

II. — Classification  of  Untanned  Calf-skins.  Untanned 
calf-skins,  the  manufacture  of  which  we  are  about  to 
describe,  may  be  divided  into  four  classes,  viz:— 

1st.  Calf-skins  fresh  from  the  butcher’s. 

2d.  Salted  calf-skins. 

3d.  Dry  French  and  European  calf-skins. 

4th.  Dry  calf-skins  from  the  East  and  West  Indies. 

Washings. — On  receiving  the  skins  fresh  from  the 
butcher,  they  are  placed  in  water  for  washing;  not  in 
running  water,  because  it  is  too  cold  in  winter  and  too 
warm  in  summer.  In  the  absence  of  spring  water,  we 
use  that  from  the  pits.  In  the  centre  of  the  work-house 
or  in  the  corner  is  a  large  reservoir  rising  at  least  six 
feet  above  the  ground;  there  the  water  is  collected  and 
distributed  about  the  establishment.  Soft  water  is  pre¬ 
ferred,  as  less  charged  with  calcareous  matter  than  hard 
water,  which  often  holds  in  solution  earthy  salts. 

I  use  a  pit  built  of  wood.  As  soon  as  the  skins  come 
from  the  butcher  I  plunge  them  into  this  pit,  unfolding 
them  one  by  one,  and  being  careful  to  scatter  them 
about  the  vessel  with  a  stick. 


248 


TANNING. 


One  hundred  calf-skins  weighing  from  1000  to  1200 
lbs.  are  enough  for  any  allowance  of  water  ;  fewer  may 
be  taken,  but  if  more  are  put  in  they  will  not  be  well 
cleaned.  In  summer  I  let  the  skins  soak  six  hours,  and 
twelve  hours  in  winter,  according  as  the  temperature 
rises  or  falls,  after  which  I  take  them  out  of  the  water. 
Then  I  empty  the  pits  and  refill  them  with  clear  water, 
and  replace  the  skins  as  at  first.  In  about  six  hours  in 
summer  and  twelve  in  winter  I  examine  them,  the  flesh 
is  white,  the  little  veins  have  lost  their  blood.  I  draw 
them  and  give  them,  while  on  the  horse,  light  blows 
with  the  iron  on  the  flesh  side. 

Liming. — -The  calf-skins  being  now  sufficiently  cleansed 
and  drained,  I  set  about  placing  them  in  lime-pits.  The 
lime-pits  are  three  in  number,  each  52  cubic  feet.  In 
one  is  the  dead  liquor  or  the  oldest,  in  another  the  gray 
or  the  second  in  strength,  and  in  the  third  the  fresh 
strong  lime,  which  is  the  most  active.  By  means  of  a 
large  hoe,  I  agitate  the  contents  of  the  dead  vat  as  much 
as  possible,  and  when  sufficiently  stirred  I  cast  in  my 
calf-skins,  one  by  one,  unfolding  them  well  and  sinking 
them  in  the  liquid  as  fast  as  I  plunge  them  in.  This 
done,  they  are  left  undisturbed  for  twenty-four  hours ; 
at  the  end  of  which  they  are  drawn  off  with  iron 
tongs.  When  they  are  out  I  stir  up  the  lime-water 
anew,  and  immerse  the  skins  in  it  for  another  twenty- 
four  hours. 

This  is  done  with  fresh  skins  from  the  butcher ;  but 
if  they  are  slightly  tainted,  I  pass  them  in  the  gray 
solution,  and  even  into  the  strongest  one,  in  order  to 
help  their  preservation.  If  they  begin  to  decompose 
when  received  from  the  butcher,  I  rinse  them  carefully, 
beat  them  on  the  flesh  side,  and  cast  them  immediately 
into  the  strongest  lime-pit.  I  take  up  the  skins  which 
have  been  immersed  in  the  dead  solution  for  the  second 
twenty-four  hours ;  I  pass  them  into  the  second  solu¬ 
tion,  where  they  are  worked  as  in  the  first,  and  left 
forty-eight  hours,  being  careful  to  raise  and  beat  them 
after  each  twenty-four  hours. 

At  the  end  of  these  four  days  of  liming,  it  frequently 


TANNING  OF  CALF-SKINS. 


249 


happens  in  summer  that  a  third,  a  half,  sometimes  even 
all  the  skins  are  stripped  of  hair.  In  such  a  case  they 
are  immediately  taken  out;  otherwise,  I  pass  them  in 
the  quick  vat,  where  I  leave  them  until  the  process  is 
completed.  But,  generally,  in  twenty-four  or  forty- 
eight  hours  the  end  is  attained.  I  allow  the  skins  to 
drain,  and  put  them  into  a  tub  with  just  water  enough 
to  cover  without  floating  them  ;  there  they  are  submitted 
to  the  first  disgorging  process.  They  can,  if  necessary, 
remain  in  this  water  ten  or  twelve  days. 

I  prefer  this  method  to  piling,  for  in  the  water  calf¬ 
skin  parts  with  the  lime,  and  the  action  of  the  latter  is 
weakened.  While  in  the  pile  it  continues  to  work,  and 
if  my  men  in  piling  do  not  exercise  care,  they  catch 
what  curriers  call  the  plis  de  pelain ,  a  disease  almost 
impossible  to  banish  from  currying  establishments.  But 
the  sum  of  ^11  this  is,  as  soon  as  the  skins  are  unhaired, 
they  are  to  be  taken  out  and  rinsed  in  a  vat  or  washed 
immediately  in  the  river ;  in  the  first  process,  then,  it 
is  advisable  to  be  as  quick  as  possible,  for  I  repeat 
that  liming  of  calf-skins  is  not  tanning  them.  We  have 
heretofore  omitted  to  indicate  the  manner  in  which  the 
three  pits,  called  the  strong,  gray,  and  slake  pits,  are 
prepared. 

Into  my  pit,  the  capacity  of  which  is  about  fifty-two 
cubic  feet,  I  turn  about  one  hundred  and  ninety-eight 
gallons  of  water,  and  add  thirty-nine  gallons  of  fat  lime; 
this  is  for  the  strong  pit.  In  the  gray  pit  I  mingle  the 
same  quantity  of  water  and  twenty-five  gallons  of  lime; 
in  the  dead  put  for  the  same  quantity  of  water  from 
twelve  to  fifteen  gallons  of  lime. 

I  keep  alive  my  pits  while  they  are  in  use  with  slacked 
lime,  in  such  a  way  as  to  preserve  the  relative  strength. 
I  renew  my  live  pit ;  for  about  every  six  weeks,  or  at 
most  two  months,  it  degenerates  to  the  strength  of  the 
gray  pit,  and  the  gray  pit  to  that  of  the  slack.  In 
order  to  remake  the  live  pit,  I  first  empty  and  cleanse 
the  dead  pit,  for  I  believe  this  step  to  be  necessary  to 
the  health  of  the  workmen  and  salubrity  of  the  estab¬ 
lishment. 


250 


TANNING. 


Salted  Skins. — These  hides  are  cleansed  from  the  salt 
and  blood  in  twenty-four  hours ;  then  they  are  taken 
from  the  water  and  struck  with  the  iron  upon  the  fresh 
side,  then  replaced  in  clean  water  for  twelve  hours,  after 
which  they  are  removed  and  allowed  to  drain  off ;  finally, 
they  are  put  into  the  slake  pit,  following  the  same 
course  as  with  fresh  skins. 

Dried  Calf-skins. — For  calf-skins,  dried  in  hair  from 
France  and  other  parts  of  Europe,  I  pursue  the  follow¬ 
ing  method : — 

The  skins  are  soaked  forty-eight  hours;  at  the  ex¬ 
piration  of  that  time  I  raise  and  lower  them  in  the 
same  water,  and  let  them  remain  another  forty-eight 
hours.  I  then  raise  them  again  and  straighten  them 
very  carefully  with  the  stretching  iron,  especially  on  the 
parts  not  affected  by  the  soaking. 

The  edges  and  the  necks  should  be  worked  with 
minute  attention  ;  every  fold  should  be  opened,  and  the 
stiff  parts  of  the  neck  should  be  unrolled  with  the  hand. 
This  work  finished,  and  I  replace  them  in  water  for 
twelve  hours,  then  withdraw  them,  let  them  drain,  and 
send  them  to  the  dead  pit,  which  I  have  taken  care  to 
weaken,  because,  for  calf-skins  dried  in  the  air,  the  pits 
ought  not  to  be  so  strong  as  for  salted  and  fresh  calf¬ 
skins. 

I  use  this  method  of  softening  dry  skins  during  about 
eight  or  nine  months  in  the  year,  but  when  the  tempe¬ 
rature  falls,  my  remedy  is  found  in  my  wells  of  water. 
It  is  very  rare  that  in  a  tannery  one  has  not  one  pit 
unoccupied ;  availing  myself  of  this  pit,  I  pile  in  it  as 
many  dry  calf-skins  as  it  can  hold,  and  having  covered 
them  with  heavy  stones,  set  my  pump  in  motion,  and, 
instead  of  sending  the  water  into  the  reservoir,  direct  it 
all  warm  into  the  pit  where  the  skins  are.  I  fill  this 
pit  with  water,  place  three  or  four  poles  over  it,  and 
carefully  cover  the  whole  with  empty  bags  in  such  a 
manner  as  to  exclude  the  air  as  far  as  possible.  This 
done,  I  wait  48  hours  for  the  light  skins  and  62  for  the 
heavy.  The  water  in  the  pit  undergoes  a  partial 
fermentation,  and  at  the  end  of  this  time  the  calf-skins, 


TANNING  OF  CALF-SKINS. 


251 


perfectly  restored,  may  receive  the  action  of  the  stretch¬ 
ing-iron. 

Dry  Calf-Shins  from  Foreign  Countries. — This  class  of 
skins  is  of  Eastern  production ;  they  come  from  Madras, 
Calcutta,  Java,  etc.  etc.  In  France  few  of  these  skins 
are  tanned,  but  in  England  and  Germany  considerable 
quantities  are  manufactured. 

To  soften  them  I  put  them  to  soak  in  my  vat  for 
three  or  four  days,  and  then  withdraw  and  pile  them 
up.  When  well  drained,  I  give  them  heavy  blows  with 
the  iron ;  the  water  worker  by  the  strength  of  his  arm 
must  tear  away  the  fatty  tissues,  the  thin  skin  which 
envelops  the  hide ;  he  thus  frees  it,  breaks  down  its 
contractility,  and  expands  it  one-third.  When  this  work 
is  done  intelligently  and  boldly,  it  may  be  taken  for 
granted  that  the  skins  will  be  well  softened.  I  replace 
them  in  clean  water  and  leave  them  there  24  or  48 
hours,  according  to  the  season  of  the  year ;  they  are  then 
worked  on  the  hair  side,  and  in  the  direction  that  the 
hair  runs.  This  done,  they  are  piled  one  above  another, 
the  best  on  the  top,  and  the  following  solution  is  applied : 
For  about  100  skins,  weighing  from  6  to  8  lbs.  each,  I  take 
a  cask  holding  about  50  galls.,  fill  it  two- thirds  full  of 
water,  and  throw  in  some  good  lime  so  as  to  make  it 
boil  for  a  time.  While  still  warm,  add  4  lbs.  of  orpi- 
ment,  mix  the  whole,  and  let  it  cool.  I  proceed  as 
follows:  To  the  end  of  an  old  broom  I  tie  a  stout  piece 
of  linen  canvas,  and  soap  this  mop  in  the  liquid,  and 
make  an  application  of  it  to  the  hair  of  the  skin. 
When  well  smeared,  I  bend  it  double,  as  one  would  a 
hide  in  salting  it,  and  deposit  it  in  a  vault  constructed 
for  the  purpose.  The  same  course  is  pursued  with  all 
the  skins,  taking  care  to  pile  them  in  the  vat,  in  the  best 
possible  manner,  and  when  the  last  is  reached,  I  pour 
the  remainder  of  the  solution  over  all  the  skins,  so  as  to 
cover  them.  They  are  thus  left  for  three  days;  on  the 
fourth  they  are  withdrawn  from  the  vat,  and  I  rinse 
them  in  running  water ;  I  leave  them  to  drain  and  place 
them  for  24  hours  on  a  solid  platform  in  order  to  have 


252 


TANNING. 


them  swell  a  little.  At  the  end  of  this  time  I  prepare 
for  the  river  work. 

River  Work. — The  river  work  must  be  arranged  so 
that  the  men  lose  the  least  possible  time  in  taking  out 
and  replacing  in  the  tubs  the  skins  that  they  are  making. 

Three  tubs  are  necessary  to  five  or  six  men  working 
with  a  bench  ;  these  tubs  should  be  of  a  capacity  of  from 
375  to  400  galls,  each,  and  the  water  should  be  intro¬ 
duced  and  drained  off  quickly. 

The  working  benches  are  four  and  a  half  feet  long, 
and  they  are  all  covered  with  a  heavy  plating  of  zinc, 
giving  an  even  surface,  in  order  to  facilitate  operations, 
and  to  avoid  breaks  on  the  hair  side,  and  knife  cuts. 

The  sheet  of  zinc  is  three  feet  long  by  two  feet  broad, 
and  the  bench  is  arched  about  seven  inches. 

The  zinc  is  fastened  down  by  round-headed  nails  well 
driven  in  ;  it  should  not  reach  the  head  of  the  table,  but 
about  one  inch  lower,  for  the  following  reason :  It  often 
happens  in  working,  that  one  is  obliged  to  lay  from  20 
to  25  calf-skins  on  a  table  to  drain  off,  and  to  leave  them 
there  during  several  hours.  And  I  have  noticed  that 
the  undermost  skin  having  the  hair  side  next  the  border 
of  the  head  of  the  table  becomes  strongly  marked  with 
a  curve  in  the  neck,  and  that  this  impress  cannot  be 
effaced  either  in  the  tanning  or  currying.  The  hair 
side  at  this  spot  became  like  parchment,  and  would  not 
absorb  the  tannin.  I  looked  and  attributed  this  to  the 
ridges  of  my  tables.  I  brought  my  sheet  of  zinc  one 
inch  lower,  and  from  that  time  I  found  no  more  wrinkles 
on  the  hair  side  of  my  skins. 

The  table  for  rounding  off  skins,  and  for  thinning  the 
neck  is  broader,  and  less  arched  than  the  other;  it  is 
lens  shaped.  This  facilitates  the  work  of  the  knife,  for 
by  having  a  broader  surface,  the  edge  is  less  liable  to 
make  flaws,  and  the  work  progresses  more  rapidly,  as  the 
operator  is  not  forced  to  change  the  position  of  his  calf¬ 
skins  so  often,  and  when  he  reduces  a  throat  or  a  head, 
he  does  so  in  a  more  uniform  manner. 

The  tools  we  use  are : — 


TANNING  OF  CALF-SKINS. 


253 


1st.  A  knife  having  a  blade  one  and  a  half  foot  long, 
and  provided  at  either  end  with  convenient  handles. 

2d.  A  tanner’s  knife  with  a  strong  handle ;  the  blade 
should  be  13  inches  long,  and  the  curve  nearly  one  inch. 

3d.  A  smoothing  stone,  having  the  stone  part  11 
inches  long,  fixed  in  a  holder  or  perforated  iron,  and  held 
in  its  place  by  iron  rivets.  Its  curvature  should  be 
about  one  inch,  and  the  handles  should  be  strong  and 
solid. 

It  is  necessary  that  each  workman  should  have  a 
double  set  of  tools,  namely,  two  No.  1  knives,  one  lighter 
than  the  other,  and  that  most  used  necessarily  becomes 
the  lighter  of  the  two;  then  two  knives  No.  2,  one  to 
depilate  and  work  on  the  hair  side,  another  to  flesh  and 
work  the  skins;  one  good  smoothing  is  sufficient. 

Operation  First.- — The  first  operation  is  the  depila- 
tion.  In  order  to  depilate  freshly  slaughtered  calf-skins, 
I  place  on  the  table  two  skins  as  substratum;  for  me¬ 
dium  skins  three,  and  four  for  middle  skins. 

To  avoid  scratches  and  to  make  the  action  of  the  knife 
easier,  the  workman  must  give  great  care  to  the  edge, 
and  leave  no  trace  of  hair  upon  them ;  then  I  place  them 
in  water,  and  rinse  them. 

Next  a  skilful  workman  removes  the  necks;  he  cuts 
the  navels  and  nipples,  trims  the  rump  and  the  tail, 
going  entirely  around  the  skin,  and  reaches  the  throat. 

After  this  operation  the  skins  are  folded  crossways, 
starting  from  the  lump  on  the  shoulder.  In  working 
fresh  slaughtered  hides  I  lay  them  on  a  bare  table,  but 
for  small  medium  sized  or  thin  skins  I  lay  two  skins 
underneath,  to  avoid  breaking  the  hair  side. 

To  execute  this  operation  well,  short  quick  strokes 
should  be  given  with  the  knife,  allowing  the  edge  to 
cut  as  little  as  possible.  The  work  should  be  sharply 
and  briskly  done  upon  the  cripper,  where  the  nerve  of 
the  skin  should  be  entirely  crushed,  but  the  hinder 
flanks  and  towards  the  breasts  should  be  passed  over 
lightly,  without  even  attempting  to  take  off  the  tissue 
covering  these  parts.  The  neck  should  be  treated  care¬ 
fully,  and  the  throats  and  heads,  when  the  skins  have 


254 


TANNING. 


them,  should  be  briskly  worked.  By  pursuing  this 
course  the  nerves  of  the  calf-skins  are  crushed  on  the 
nervous  parts,  and  the  weak  or  hollow  spots  are  spared. 
After  the  skins  have  all  undergone  this  process  I  soak 
them  six  hours  in  a  tub  of  clean  water. 

I  next  give  them  a  counter-fleshing,  placing  two  skins 
as  a  layer  on  the  table.  I  return  them  to  the  water  for 
an  hour,  I  then  take  them  out  to  work  them;  for  this 
purpose  I  lay  on  the  table,  when  the  skins  are  fresh,  two 
for  foundations,  and  more  if  they  are  small  skins.  I  use 
the  stone  lightly  at  first,  and  then  smartly,  to  rid  the 
skins  of  lime.  After  using  the  stone  I  clean  the  hair 
side  with  a  knife  not  too  sharply  whetted,  so  as  to  avoid 
scratches.  Then  I  put  the  calf-skins  again  to  soak  in 
clean  water  during  three  or  four  hours;  at  the  end  of 
this  time  I  take  them  out  in  order  to  work  them  once 
more  on  both  sides.  I  then  rinse  them  for  the  last  time, 
and  stack  them  up  until  I  am  ready  to  put  them  in  the 
vats. 

In  order  that  my  manner  of  conducting  my  dressing, 
and  that  the  whole  of  my  work  may  be  well  understood, 
I  am  obliged  to  enter  into  indispensable  details.  In  the 
first  place  I  have  to  fix  a  basis  of  fabrication,  and  deter¬ 
mine  as  clearly  as  possible  how  many  skins  I  can  pro¬ 
duce  in  the  course  of  a  year  by  my  method  of  management, 
the  number  of  operations  I  must  employ,  the  quantity 
of  tan  which  I  require  to  provide  myself  with;  in  a 
word,  I  have  to  estimate  approximately  the  price  of  calf¬ 
skins  when  tanned  and  in  the  pits. 

I  will  adopt  as  a  basis  the  manufacture  of  12,000  calf¬ 
skins  per  annum,  such  as  they  come  from  the  general 
slaughter-house.  We  reckon  these  skins,  large  and  me¬ 
dium  together,  as  weighing,  one  with  the  other,  14|  lbs. 
each.  We  have,  therefore,  174,000  lbs.  of  fresh  hides 
to  tan,  and  I  use  three  pounds  of  tan  to  one  pound  of 
fresh  hide.  I  shall  have  to  provide  myself  with  522,000 
lbs.  of  tan.  Reckoning  extra  heavy  skins,  which  will 
require  three  layers  and  a  large  piece  of  bark  which  I 
use  in  my  liquor  vats,  I  may  estimate  the  amount  at 
555,000  lbs.  of  tan  to  be  used  during  the  year. 


TANNING  OF  CALF-SKINS. 


255 


Six  men  at  the  lime  pits  and  river  work  will  suffice, 
and  two  men  for  dressing  and  to  tend  the  pits,  can  do 
the  work,  with  the  help  from  time  to  time  of  one  of  the 
men  employed  in  the  river  work. 

The  foreman  intrusted  with  the  management  of  the 
lime  pits  and  with  the  river  work,  will  work  with  the 
men  and  turn  the  skins.  These  men  will  turn  250  calf¬ 
skins  weekly.  The  foreman  dresser  will  attend  to  the 
pit,  make  his  liquors  and  return  the  skins  to  the  pit. 
A  good  workman  will  be  assigned  to  aid  him,  and  as  it 
is  necessary  they  understand  well  each  other,  it  is  better 
to  leave  the  choice  of  the  assistant  to  the  foreman.  The 
same  is  done  in  regard  to  the  foreman  of  the  river  work. 

The  staff  of  workmen  being  well  organized,  my  pits 
well  arranged,  and  my  river  work  complete,  we  next 
come  to  the  dressing  operation. 

In  order  to  work  1000  calf-skins  monthly  we  need  26 
vats  of  oak  wood,  three  feet  in  depth  by  live  feet  and 
one  half  in  diameter.  They  should  be  of  oak,  for  the 
edges  of  a  pine  vat  cannot  long  stand  the  daily  work  to 
which  they  are  subjected. 

Twenty-six  vats  with  50  calf-skins  in  each  will  work 
1300  skins  monthly,  but  as  we  have  vats  of  large  skins, 
only  32  of  which  can  be  held,  the  number  becomes  re¬ 
duced  to  1000 ;  for  before  preparing  the  river  work  for 
a  vatful,  we  equalize  the  weight  of  the  skins  intended 
for  that  vat  as  much  as  possible.  50  medium  skins 
weighing  13  lbs.  each,  make  600  lbs.  of  fresh  hides  for 
our  vat,  and  if  having  calf-skins,  only  put  in  35, 
weighing  on  an  average  17  lbs.  each,  making  612  lbs.  in 
all.  It  is  very  important  that  the  contents  of  the  vats 
should  be  equalized,  so  that  the  quantity  of  tan  used  in 
each  may  secure  the  same  result,  and  in  order  to  reach 
accuracy  in  this,  we  weigh  all  the  calf-skins  as  they 
come  from  the  butcher.  The  weight  is  marked  on  each, 
and  before  putting  a  lot  to  soak,  the  foreman  reckons  up 
the  aggregate  weight,  so  as  not  to  exceed  the  limit  of 
612  lbs.  of  fresh  hides. 

We  give  the  calf-skins  six  days  in  the  liquor,  and  as 


256 


TANNING. 


we  can  put  100  skins  in  each  vat,  we  therefore  require 
six  vats  for  this  operation. 

In  the  handling  we  put  200  skins  together,  and  leave 
them  during  one  month,  consequently  we  require  six 
large  vats  for  this  process.  They  may  be  built  of  pine, 
and  should  be  5z  feet  in  depth  and  feet  broad. 
They  are  raised  1  i  foot  above  the  level  of  the  ground  to 
prevent  their  being  stepped  on.  The  oak  vats  first  men 
tioned  should  also  rise  lz  foot  above  the  ground  in  order 
to  assist  the  workman  who  stirs  the  hides  by  offering  a 
support  to  his  knees  on  the  edges.  The  risk  of  his 
pitching  in  is  thus  avoided ;  still,  despite  this  precau¬ 
tion,  it  happens  that  a  man  will  plunge  head  foremost 
into  a  vat  now  and  then.  This  seldom  occurs,  but  it 
lias  happened,  and  we  have  witnessed  it. 

We  need  also  12  racks  of  solid  oak  capable  of  sup¬ 
porting  100  calf-skins  if  necessary.  We  lay  the  skins 
to  drain  on  the  frames  when  we  take  them  out  of  the 
vat,  to  turn  over  the  contents  and  to  add  the  quantity 
of  tan  necessary,  when  they  are  returned  to  the  vat. 

The  vat  is  entirely  covered  with  bitumen  so  as  to  pre¬ 
vent  it  from  rotting  at  the  level  of  the  ground,  and  it  is 
also  more  clean.  If  the  row  of  vats  is  against  the  wall, 
fill  in  the  intermediate  vats  and  apply  bitumen  to  the 
intervals  between  them,  so  that  when  the  skins  are 
stirred,  the  ooze  falls  back  into  the  vat  and  is  not  lost. 

Twenty-six  vats  in  operation  for  the  dressing  liquor, 
six  vats  for  the  liquors,  six  large  ones  for  handling,  total 
38,  to  which  number  two  more  are  added  to  provide 
against  accidents  or  unforeseen  stoppages,  making  in  all 
40  vats ;  and  as  we  require  at  least  four  vats  to  each 
pit,  although  the  calf-skins  remain  longer  in  the  pits 
than  in  the  vat,  we  have  ten  pits.  They  are  6^  feet  in 
depth  and  7  feet  in  breadth  at  the  mouth.  They  will 
hold  about  300  calf-skins,  and  we  do  not  have  them 
larger,  so  as  to  use  one  a  week.  This  is  the  result  of 
the  general  arrangement  of  our  work,  which  should  pro¬ 
gress  steadily  without  any  stoppage. 

We  require  also  three  ooze  pits,  which  are  also  6| 
feet  in  depth  and  7  feet  in  breadth.  We  lay  in  them 


TANNING  OF  CALF-SKINS. 


257 


a  double  flooring  of  pine  pierced  with  holes  for  the 
ooze  to  filter  through.  Then  we  have  a  square  upper 
work  of  plank  to  hold  the  pump,  which  reaches  down 
to  the  double  floor. 

In  the  new  pit,  which  we  will  designate  under  the 
name  of  ooze  pit  No.  1,  we  lay  from  18  to  24  inches 
deep  of  coarse  bark  to  support  the  ooze.  In  it  we  place 
the  spent  tan  of  the  first  and  second  pulverization,  and 
it  serves  to  prepare  the  third  vats  as  well  as  to  aid  the 
strength  of  a  feeding  vat.  At  the  end  of  a  week  this 
becomes  pit  No.  2  ;  its  liquor  serves  to  fill  my  pits.  At 
the  end  of  a  week  this  becomes  pit  No.  3,  whose  strength 
is  almost  negative,  but  which  serves  to  keep  pit  No.  2 
from  giving  out  too  soon ;  it  receives  the  spent  tan  of 
the  last  set  of  pits,  and  the  liquor  of  the  second  ;  in  a 
word  it  filters  the  last  essence  of  the  spent  tan,  and  it 
serves  also  sometimes  to  modify  the  strength  of  pit  No. 
1,  when  we  prepare  a  third  vat.  At  the  end  of  a  week 
it  becomes  totally  exhausted ;  then  we  have  it  emptied 
among  the  spent  tan,  and  use  it  again  as  a  new  pit,  and 
thus  continually.  These  ooze  pits  aie  of  the  greatest 
utility,  and  nothing  can  be  done  well  without  their  em¬ 
ployment. 

Having  given  a  sufficiently  full  account  of  the  mate 
rial  arrangement  of  the  factory,  we  come  now  to  the 
operation  of  placing  the  calf- skins  in  the  vats. 

The  third  vat,  which  is  the  last  given,  is  always  a  new 
one;  the  liquor  pit  No.  1  serves  to  prepare  it.  Its 
strength  should  be  about  3°  by  the  tanninometer,  less 
rather  than  more.  It  becomes  the  second  vat,  and  the 
second  vat  becomes  the  first,  and  the  first  becomes  the 
discharging  vat.  We  only  use  the  tanninometer  for  the 
third  vat,  for  this  instrument  gives  only  the  strength  of 
the  liquor  when  this  liquor  is  free  from  all  gelatine.  It 
would  not  be  successfully  used  to  estimate  the  second 
vat,  whose  liquor  is  already  charged  with  gelatine.  The 
same  applies  with  regard  to  the  first  and  also  to  the  dis¬ 
charging  vat.  The  latter  is  prepared  in  the  following 
manner:  Begin  by  extracting  one-half  of  the  spent  tan 
and  taste  it ;  its  liquor  should  be  barely  able  to  affect  the 
17 


258 


TANNING. 


palate,  and  as  it  is  almost  always  too  strong,  add  to  it 
liquor  from  the  pit  No.  3,  and  fill  it  about  two- thirds 
full,  so  that  when  the  calf-skins  are  placed  in  it,  the 
whole  contents  will  reach  to  about  six  inches  from  the 
top.  Have  the  calf-skins  brought  up  from  the  river- 
work.  The  workman  takes  them  one  by  one  and  lays 
them  flat  in  the  vats.  Another  man,  armed  with  a  long 
oak  wood  pole,  of  the  length  of  about  five  feet,  plunges 
them  down  the  one  after  the  other  all  around  the  vat. 
After  this  operation,  the  same  man  takes  a  longer  pole, 
also  of  oak  wood  eight  feet  long,  and  strong  enough  not 
to  bend  too  much  under  the  weight  of  the  load.  He 
plunges  it  along  the  sides  and  uses  it  as  a  lever.  From 
12  to  15  calf-skins  are  at  the  end  of  his  pole,  which  he 
lowers  on  the  edge  of  the  vat  and  swings  them  right 
and  left  for  about  ten  minutes. 

In  this  manner  he  sets  the  entire  contents  of  the  vat 
in  motion,  and  then  raising  his  pole  two-thirds,  he  makes 
it  describe  half  a  circle  to  the  left,  then  raises  up  his 
pole  and  lets  the  skins  go,  plunges  in  again,  seizing 
about  the  same  number  of  skins,  and  continues  in  this 
manner  until  he  has  gone  completely  around  the  vat; 
then  he  takes  a  tanner’s  iron  hook,  disentangles  the 
skins,  equalizing  his  vat,  and  recommences  his  work 
with  the  pole,  and  so  on  during  two  hours.  At  the  end 
of  this  time,  the  calf-skins  being  well  cleaned  and  well 
washed,  will  have  lost  all  the  lime  remaining  in  them 
after  the  river  work.  This  operation  is  complete  when 
the  flesh  of  the  skin  begins  to  turn  black;  then  they 
are  promptly  taken  out  by  the  two  men,  one  fishes  for 
them  with  the  hook,  and  the  other  takes  them  one  by 
one  and  places  them  on  the  rack,  and  this  operation 
being  speedily  ended,  they  are  carried  in  a  wheelbarrow 
to  the  first  vat,  which  is  prepared  in  advance  in  the  fol¬ 
lowing  manner. 

All  the  spent  tan  is  extracted  and  tasted,  and  as  its 
juice  is  always  too  strong,  add  to  it  some  barrels  from 
the  liquor  pit  No.  3.  Fill  it  two-thirds  full,  and  throw 
the  skins  into  it,  in  the  same  manner  as  in  the  dis- 


TANNING  OF  CALF-SKINS. 


259 


charging  vat,  the  workman  continuing  to  swing  them 
in  the  same  manner. 

The  flesh  of  the  skins  begins  to  bleach  at  the  end  of 
an  hour;  throw  in  11  lbs.  of  fine  tan  of  the  best  quality, 
and  continue  to  stir  them.  A  quarter  of  an  hour  later, 
add  a  like  quantity  of  tan,  and  the  stirring  continues ; 
at  the  end  of  another  quarter  of  an  hour,  examine  the 
skins,  and  you  find  that  a  slight  grain  begins  to  appear 
on  the  hair  side.  Stir  them  then  during  a  quarter  of  an 
hour  longer,  putting  in  11  lbs.  more  of  fine  tan,  and 
when  you  are  certain  that  the  grain  is  well  worked, 
wishing  to  obtain  more  (so  as  not  to  affect  the  hair  side 
by  trying  to  get  a  premature  grain),  remove  them 
promptly  to  the  rack  placed  above  the  grain.  Then  stir 
the  vat  with  a  stirring  pole;  the  second  workman  takes 
a  wooden  shovel  and  works  the  liquor,  while  the  other 
workman  stirs.  Then  plunge  back  the  skins  again  into 
the  vat,  one  by  one,  briskly,  taking  care  to  watch  that 
the  workman  performing  this  does  not  drive  them  to 
the  bottom  with  the  first  stroke  of  his  pole;  after  he  has 
plunged  a  skin  about  half-way  down,  he  should  change 
the  place  of  his  pole,  in  order  to  avoid  making  folds  in 
the  skin,  or,  as  they  are  called  in  tanners’  language, 
umbrellas.  By  beginning  the  stirring  operation  at  six 
in  the  morning,  it  is  finished  by  ten  o’clock;  but  leave 
the  skins  quiet  till  noon,  then  take  them  out  and  lay  on 
the  rack,  folded  in  half  from  the  rump  to  the  head,  with 
the  hair  side  inwards.  Stir  the  vat  again,  and  plunge 
the  skins  in  once  more,  adding  the  while  3  lbs.  of  tan, 
of  the  best  quality,  ground  to  nut  size.  At  three  o’clock 
repeat  the  operation,  except  that  you  add  no  tan,  stir 
the  vat  briskly,  so  that  the  froth  rises  to  the  top,  put  the 
skins  in,  and  at  six  o’clock  take  them  out.  Stir  the  vat 
as  usual,  and,  replacing  the  skins,  add  20  lbs.  more  of 
the  same  kind  of  tan.  Above  the  vat  is  a  board  painted 
black,  upon  which  you  write  the  day  that  the  skins  are 
first  placed  in  the  vat,  the  number  of  skins  contained 
therein,  and  score  two  bars  to  indicate  that  88  lbs.  of 
tan  have  been  put  in  the  vat. 

Next  day,  as  soon  as  the  workmen  arrive,  look  at  the 


260 


TANNING. 


vat,  examine  the  hair  side  of  the  skin;  the  grain  begins 
already  to  be  better  defined ;  stir  the  contents  vigorously, 
and  while  the  skins  are  being  again  plunged  into  the 
vat,  add  22  lbs.  of  tan,  nut  size,  and  then  leave  the  skins 
alone  the  whole  dav.  At  six  o’clock  in  the  evening 
raise  the  vat,  and  proceed  in  the  same  manner  as  before, 
but  in  replacing  the  skins  in  the  vat,  add  22  lbs.  of  tan. 
Next  day  raise  the  skins  again,  and  add  20  lbs.  then, 
and  20  lbs.  more  when  the  skins  are  replaced  in  the  vat, 
stirring  the  while.  Next  day  the  operation  is  repeated, 
after  which  they  are  allowed  to  remain  undisturbed 
during  four  entire  days.  The  first  vat  has  taken  about 
220  lbs.,  but  gradually,  so  that  the  grain  of  the  skins 
cannot  be  affected.  Throw  out  the  contents  of  the  dis¬ 
charging  vat,  and  take  care  not  to  have  it  put  into  the 
liquor  pits,  for  this  liquor  contains  too  much  lime  and 
gelatinous  matter;  this  liquid  would  injure  the  purity 
of  the  liquor  pits. 

In  many  tanneries  the  stirring  is  done  with  a  shovel, 
and  in  large  establishments  where  there  is  mechanical 
motive  power,  the  stirring  is  effected  by  the  agency  of 
floating  mills  in  order  to  economize  manual  labor;  this 
is  an  improvement,  but  the  floaters  should  not  be  abused, 
for  if  used  without  caution,  they  often  scrape  the  skin. 

Upon  the  ninth  day  after  the  skins  have  been  placed 
in  the  vat,  have  them  taken  out  and  drained  on  the 
frame  one  hour.  Then  prepare  the  second  vat.  Have 
all  the  spent  tan  which  it  holds  taken  out  in  order  to 
assure  the  strength  of  its  liquor.  Taste  it  and  add 
almost  always  two  pailfuls  of  liquor  of  the  pit  No.  1, 
and  one  pailful  of  the  pit  No.  3  or  No.  2,  according  as  it 
is  more  or  less  to  the  required  degree.  In  order  to  aid 
the  estimate,  take  care  to  taste  the  liquor  of  the  first 
vat,  and  raise  the  strength  of  the  second  about  one  de¬ 
gree  above  the  first.  Have  22  lbs.  of  tan,  nut  size, 
thrown  into  it,  and  stir  it  strongly  for  five  minutes ;  then 
have  the  skins  brought  to  the  frame  above  No.  2;  agi¬ 
tate  its  contents  again,  and  do  not  wait  before  putting 
in  the  skins  for  the  liquor  to  become  still,  on  the  con¬ 
trary  put  them  in  quickly,  and  after  about  two-thirds  of 


TANNING  OF  CALF-SKINS. 


261 


them  are  in  the  vat,  throw  on  about  11  lbs.  of  tan  and 
keep  on.  When  the  last  skin  is  reached,  two  men  pack 
the  skins  well  down  on  the  bottom  of  the  vat,  so  as  to 
exclude  the  air,  and  then  throw  upon  them  the  11  lbs. 
of  tan  remaining.  This  operation  is  repeated  each 
morning  for  four  days,  adding  each  time  44  lbs.  of 
coarse  tan  of  the  best  quality ;  and  take  care  each  day 
to  have  the  skins  drained  for  one  hour  on  the  frame, 
between  the  time  of  taking  out  and  of  replacing  them. 
The  day  that  the  operation  is  begun,  mark  on  the  board 
the  number  of  skins  placed  in  the  vat,  and  the  quan¬ 
tity  of  tan  put  in,  and  after  the  fourth  day,  leave  them 
quiet  for  four  days  in  summer  and  six  in  winter.  The 
skins  therefore  remain  in  the  second  vat  during1  eight 
days  in  summer  and  ten  days  in  winter.  Each  day  ex¬ 
amine  the  progress  made  by  the  skins.  If  they  rise  too 
much,  diminish  the  quantity  of  tan ;  if,  on  the  contrary, 
the  skins  seem  to  be  sinking  down,  put  in  20  lbs.  of  fine 
tan,  and  often  even  a  bucketful  of  liquor  from  the  vat 
No.  1.  This  is  a  matter  of  practice,  and  too  much  care 
cannot  be  given  to  the  skins  while  in  the  vats.  The 
tanner  should  devote  each  forenoon  to  this  important 
matter. 

In  the  second  vat  use  about  175  lbs.  of  coarse  tan,  nut 
size,  and  of  the  best  quality,  which  will  be  sufficient  if 
the  tan  is  good.  The  ninth  or  the  tenth  day  prepare 
the  third  vat  with  the  liquor  of  the  pit  No.  1.  Fill  it 
only  half  full,  and  its  strength  should  be  about  three 
degrees  by  the  tanninometer.  If  it  is  stronger  than  that, 
reduce  it,  and  if  inferior,  throw  in  20  lbs.  of  fine  tan,  then 
let  the  contents  be  stirred  about  ten  minutes.  Next 
empty  the  second  vat  and  let  the  skins  drain  off  for  two 
hours,  when  they  are  placed  on  the  frame  of  the  third  vat, 
which  is  stirred  again,  and  22  lbs.  of  coarse  tan  are  added. 
Then  put  in  the  skins  briskly,  in  the  same  manner  fol¬ 
lowed  for  the  previous  vat.  During  four  days,  operate 
in  the  same  way,  putting  44  lbs.  of  tan  into  the  vat  each 
day,  and  the  fourth  day  leave  them  quiet.  This  vat 
takes  also  about  175  lbs.  Thus  the  preparation  of  from 
610  to  620  lbs.  of  fresh  slaughtered  skins,  has  taken, 


262 


TANNING. 


with  the  aid  of  the  liquor  pits,  about  one  lb.  of  tan  to 
every  pound  of  fresh  hides.  The  work  goes  on  gradually, 
the  hair  side  of  the  skins  remains  soft,  the  grain  comes 
out  more  and  more  each  day,  the  texture  of  the  skin  is 
slowly  and  progressively  penetrated  with  the  tannin. 
The  hair  side  becomes  as  white  as  milk,  the  skins  have 
acquired  a  certain  firmness,  the  necks  and  flanks  are  full, 
and  nothing  more  is  requisite.  Being  satisfied  now  as 
to  the  result,  leave  them  quiet  for  six  days,  taking  care 
that  the  liquor  does  not  rise  above  the  vat,  for  the  fer¬ 
mentation  that  takes  place  therein  is  often  so  active  that 
it  requires  to  be  looked  to  daily. 

In  order  to  prepare  a  vatful  of  dry  calf-skins  with  the 
hair  on,  equal  to  the  vatfuls  of  fresh  calf-skins,  put  in 
from  440  to  450  lbs.  of  skins ;  for  50  lbs.  of  fresh  skins 
do  not  give  more  than  20  lbs.  of  skins  thoroughly  dried. 
Treat  them  in  very  nearly  the  same  manner  as  the  fresh 
calf-skins,  but  have  them  stirred  an  hour  longer,  as  the 
grain  of  a  dried  calf-skin  comes  out  much  less  readily 
than  that  of  a  green  skin,  and  take  great  precautions 
that  the  grain  may  not  be  affected,  which,  having  been 
dried,  already  contracts  more  readily  under  the  action  of 
the  tannin.  Pursue  the  same  plan  for  Calcutta  and 
Java  kips.  Put  in  55  lbs.  of  skins  to  each  vatful,  for 
kips  before  they  are  dried  receive  a  preliminary  prepara¬ 
tion,  which  makes  them  much  more  difficult  to  moisten 
than  ordinary  skins. 

The  action  of  the  orpiment  used  to  depilate  them 
speedily  has  softened  the  flesh  side  a  little,  and  this 
grain  being  more  tender  requires  most  careful  treatment 
in  the  vat  process.  In  this  manner  kips  have  been 
dressed,  having  a  grain  as  soft  as  that  of  green  calf-skins, 
but  the  work  is  slower  and  requires  constant  watching. 

The  calf-skins  having  been  long  enough  in  the  vat, 
take  measures  next  for  the  treatment  with  ooze.  For 
this  purpose  clean  the  vat  in  which  you  intend  to  place 
them  and  turn  into  it  the  liquor  of  the  vat  No.  2.  Put 
about  six  inches  of  this  liquor  at  the  bottom,  and  have 
the  two  No.  3  vatfuls  raised,  those  which  you  propose 
to  use  about  three  hours  in  advance,  so  that  the  liquor 


TANNING  OF  CALF-SKINS. 


263 


may  thoroughly  drain  off.  Moisten  about  four  hundred 
and  seventy-five  pounds  of  fine  tan  of  the  best  quality. 
This  tan  you  throw  in,  a  handful  at  a  time,  upon  the 
skins  as  they  are  placed  in  layers  in  their  liquor.  It  is 
necessary  that  this  tan  should  be  lightly  sprinkled  with 
water  in  order  that  none  of  it  may  be  wasted,  and  so 
that  one  may  be  able  to  see  clearly  the  bottom  of  the 
vat.  If  it  were  not  moistened,  the  dust,  the  flour  of  the 
bark  would  be  lost,  and  the  men  would  be  incommoded 
by  it  in  their  work. 

All  these  precautions  having  been  taken,  have  the 
skins  brought  close  to  the  vat  on  a  wheelbarrow,  where 
you.  take  them  up  one  by  one.  The  first  workman  takes 
them  up  by  the  hind  legs,  and  casts  them  with  the  hair 
side  upwards  upon  the  liquor  which  covers  the  bottom 
of  the  vat.  The  second  workman*  who  is  provided  with 
a  pole,  stretches  out  the  feet  or  neck  which  may  have 
doubled  under  in  throwing  them  in;  then  the  two 
together,  each  with  a  pole,  push  the  skins  squarely  down 
into  the  liquor.  They  then  throw  in  three  or  four  hand¬ 
fuls  of  bark,  seize  another  skin,  and  the  same  operation 
is  gone  through  with  each  skin.  When  the  liquor  be¬ 
comes  all  absorbed  have  more  poured  in,  so  that  the 
skins  are  always  floating  and  yet  are  compact  as  possible. 
Care  should  be  taken  not  to  pour  in  too  great  a  quantity 
of  liquor ;  this  is  very  important,  for  with  the  com’mence- 
ment  of  this  operation  the  skins  having  floated  sufficiently 
in  the  three  vats,  should  begin  to  draw  together,  other¬ 
wise  the  fibrin  of  the  skin  will  become  too  soft  and  weak. 
For  this  stage  of  the  process  use  about  four  hundred  and 
seventy-five  pounds  of  fine  tan  of  the  best  quality,  this 
quantity  being  sufficient  for  the  fifteen  days  that  the 
skins  are  to  remain  in  the  vat.  When  the  work  is  com¬ 
plete  have  about  five  or  six  inches  of  spent  tan  laid  upon 
the  pile  so  as  to  keep  the  skins  squarely  in  the  vat ;  for 
without  this  precaution,  the  work  of  fermentation  going 
on,  the  skins  would  rise  up  and  get  out  of  the  liquor,  and 
often  in  half  a  day  they  would  leave  spots  on  the  portion 
of  the  grain  exposed  to  the  air,  and  such  stains  can 
never  be  effaced. 


264 


TANNING. 


We  have  said  that  the  skins  are  left  in  for  fifteen 
days.  At  the  end  of  this  period  have  two  vatfuls  taken 
out  and  rinsed  in  good  liquor,  and  prepare  them  for  the 
next  process,  after  allowing  them  to  drain  for  three  or 
four  hours.  This  is  how  to  proceed  in  that  operation 
which  is  done  with  the  object  of  giving  a  body  to  the 
skins  before  placing  them  in  the  pits,  and  in  order  to 
thoroughly  tan  the  grain  side  of  the  calf-skins.  In 
order  to  secure  a  white  and  soft  grain,  that  will  not 
change  color  in  currying,  this  grain  should  be  tanned 
entirely  through,  before  replacing  the  skins  in  the  pits ; 
and  this  is  the  reason  why  the  skins  are  placed  in  a 
half  floating  pit  with  the  grain  upward,  taking  care  to 
use  only  very  fine  bark,  so  as  not  to  dimple  the  grain, 
which  is  yet  tender,  and  which  has  to  undergo  a  certain 
amount  of  pressure  in  the  next  operation. 

After  having  had  the  large  vat,  in  which  it  is  in¬ 
tended  to  place  the  calf-skins  of  the  two  liquor  vats, 
carefully  cleansed,  put  in  the  bottom  of  this  vat  about 
two  inches  of  fine  spent  tan,  then  take  a  skin,  and  throw 
it  quite  flat,  with  the  grain  side  upwards,  upon  this 
layer  of  bark ;  the  men  spread  out  this  skin  with  their 
poles,  making  it  lay  quite  flat,  so  as  to  make  the  least 
creases  possible,  and  then  they  throw  handfuls  of  tan 
over  it,  especially  upon  the  centre  of  the  body  and  the 
neck,  so  that  the  grain  on  the  flanks  may  be  but  slightly 
covered,  but  the  body  of  the  skin  well  covered.  Each 
skin  has  the  same  done  to  it,  and  in  order  that  the 
layers  may  have  an  equal  depth,  have  the  tail  parts 
turned  towards  the  walls  of  the  pits,  which  equalizes 
and  regulates  its  strength.  This  operation  being  ended, 
when  you  come  to  the  last  skin,  have  it  laid  with  the 
grain  underneath.  Select  a  large  skin  for  the  last,  and 
take  care  to  cover  the  flesh  side  well  with  bark.  The 
skins  should  not  entirely  fill  up  the  vat ;  there  should 
remain  a  space  of  at  least  from  ten  to  twelve  inches 
from  the  surface  of  the  uppermost  skin  to  the  rim  of 
the  vat,  and  for  this  reason  give  to  the  contents  of  the 
pit  no  other  pressure  than  that  of  their  own  weight, 
and  the  weight  of  about  six  inches  of  spent  tan  placed 


TANNING  OF  CALF-SKINS. 


265 


at  the  top  of  it.  In  supplying  this  vat  with  juice  from 
pit  No.  1,  lay  canvas  upon  the  spent  tan,  so  that  the 
liquor,  when  poured  in,  may  not  disturb  the  bark. 
Filter  gently  and  gradually;  the  liquor  penetrates  the 
interior,  and  its  weight  makes  the  contents  rise  slightly, 
and  the  skins  bear  themselves  up.  At  the  end  of  a  day 
or  two,  after  fermentation  has  begun,  it  often  happens 
that  the  whole  mass  rises  from  ten  to  twelve  inches, 
therefore  if  the  vat  is  too  full  the  liquor  will  run  over 
and  be  lost.  For  this  reason  take  the  precaution  not 
to  fill  the  vat  clear  up  to  the  rim,  and  do  not  place  any 
weight  in  it,  because  it  is  necessary  to  have  the  skins 
float  a  little.  By  employing  a  heavy  pressure,  as  is 
done  with  skins  relaid  in  the  pits,  the  tan  would  im¬ 
print  itself  upon  the  grain  of  the  skins,  which  would 
create  difficulties  subsequently  in  the  currying  process. 
Use  no  more  tan  for  this  operation  than  in  that  pre¬ 
ceding  it,  but  the  liquor  used  to  darken  the  skins  is 
much  superior.  Then,  again,  use  a  lesser  quantity  of 
bark,  which,  however,  contains  necessarily  more  tannin 
principle  in  this  operation  than  that  which  is  used  for 
the  liquor  vats.  The  work  goes  on  progressively,  and 
the  skins  grow  more  and  more  compact.  During  this 
process  the  saturation  of  the  grain  is  completed,  without 
its  becoming  hard,  for  one  of  the  most  important  points 
is  to  tan  the  grain  thoroughly  without  rendering  it  dry, 
and  above  all  things,  if  it  is  hoped  to  curry  well,  the 
grain  should  be  soft. 

Leave  the  skins  in  this  for  one  month.  This  time  is 
enough ;  they  would  gain  nothing  by  being  left  longer. 
It  must  be  well  understood  that  each  time  that  you  take 
a  lot  of  skins  out  of  the  vats,  the  liquor  and  the  spent 
tan  contained  in  these  vats  are  removed  to  the  liquor 
vat  No.  3.  Nothing  could  be  lost  in  the  work. 

Treatment  with  Strong  Liquors. — Upon  this  stage  of 
the  operation  of  tanning  we  will  amplify  a  little. 

After  a  month  in  the  pit,  the  calf-skins  are  again 
taken  up  ;  the  grain  side  is  tanned,  it  is  white  and  well 
saturated  with  the  tanning  material,  and  since  the  ope¬ 
rations  of  working,  of  coloring,  and  of  saturating  with 


266 


TANNING. 


the  liquors  succeeded  each  other  without  interruption, 
the  grain  side  of  the  skin  almost  vanishes  under  the 
pressure  of  the  nail.  It  is  important  to  guard  against 
hardening  the  skins  by  the  employment  of  too  strong 
ooze,  and  in  order  to  avoid  this,  wash  and  rinse  them 
in  pit  No.  3.  Then  lay  them  together  in  pairs,  always 
with  the  grain  side  within,  and  let  them  drip  upon  the 
beam  for  twenty-four  hours.  Now  prepare  the  tanning 
pit  and  cover  the  bottom  with  a  layer  of  spent  tan  two 
inches  deep.  For  the  middle  layers  for  tanning  the 
skins  employ  as  much  bark  as  possible  of  the  first  quality. 
Six  hundred  and  fifty  or  eight  hundred  and  seventy- 
five  pounds  of  this  are  moistened  with  good  tanning 
liquor,  and  are  carefully  mixed.  The  moistened  mass 
is  put  in  as  small  a  compass  as  possible  in  order  to  ob¬ 
tain  for  it  a  greater  fermentation  in  the  pit.  In  every 
one  of  the  pits  there  is  a  box  made  of  boards,  which 
serves  in  watering  the  pits  to  prevent  the  bark  with 
which  the  skins  are  covered  from  being  washed  about, 
and  at  the  same  time  its  outlet  is  serviceable  in  ascer¬ 
taining  whether  there  is  sufficient  ooze  in  the  pit.  For 
eight  days  be  careful  to  see  that  the  pits  are  sufficiently 
watered  and  that  they  have  not  lost  any  tanning  liquor. 
This  is  necessary,  and  by  observing  it,  you  never  have 
pits  in  which  the  upper  skins  become  dry,  and  heat, 
and  become  greasy  on  this  account. 

When  all  these  preparations  are  made,  the  workman 
who  arranges  the  skins  descends  into  the  vat.  A  man 
is  detailed  to  assist  him,  who  hands  him  the  skins  over 
the  edge  of  the  vat,  so  that  he  can  take  them  one  after 
another  without  any  further  assistance.  The  carrier  also 
brings  him  the  tan  in  baskets,  and  the  work  begins.  He 
takes  a  skin,  folds  it  up,  the  grain  side  in,  lays  it  flat 
down,  the  tail  part  of  the  skin  directed  to  the  outside 
of  the  pit,  so  the  hind  shanks  of  the  skin,  when  they 
bend  up  together,  lie  at  the  extreme  edges.  In  this  fold 
he  puts  a  large  handful  of  tan;  he  covers  the  ends  of 
the  skin  of  the  less  afterwards  with  another  handful  of 

O 

tan.  The  tail  part  of  the  skin  and  the  part  by  the  navel 
are  also  covered  with  tan.  He  then  turns  the  fore-shanks 


TANNING  OF  CALF-SKINS. 


267 


upon  the  back  of  the  neck,  and  puts  a  handful  of  tan 
amongst  these  folds.  After  this  he  puts  a  light  covering 
upon  the  neck  and  breast,  and  here  he  puts  a  handful 
of  tan  upon  the  grain  side;  finally  he  covers  the  back 
of  the  neck,  and  the  butcher’s  cut  in  the  throat  with  a 
thick  layer,  for  those  parts  which  are  the  strongest 
have  need  of  a  double  portion  of  tan.  When  one  skin 
is  prepared  in  this  way,  the  one  who  lays  them  in  takes 
another,  and  lays  it  in  such  a  way  that  the  succeeding 
layers  shall  go  around  the  vat  in  a  circle,  so  that  they 
will  rise  regularly.  Thus  the  thinner  part  of  one  layer 
of  skins  must  be  upon  the  thicker  part  of  the  layer  be¬ 
neath,  by  which  depressions  are  avoided,  which  a  bad 
workman,  in  order  to  make  the  layers  even,  often  fills 
up  with  good  tan,  to  the  great  detriment  of  the  proprietor, 
who  often  cannot  control  this. 

A  good  arranger  of  the  pits  is  a  valuable  workman  in 
a  tannery,  for  he  makes  use  of  a  very  dear  material. 
When  the  skin  is  left  in  the  vat  the  workman  tries  it 
with  his  fingers,  and  thus  knows  how  to  estimate  how 
much  tan  should  be  applied  to  it. 

In  the  first  pit,  one  should  not  spare  the  tan,  and  it 
must  be  wet  with  good  tan  liquor.  The  liquor  of  vat 
No.  2  serves  for  this  purpose;  as  soon  as  the  workman 
has  come  to  within  eight  or  ten  inches  from  the  brim 
he  stops  laying  in,  and  throws  upon  the  last  layer  of 
skins  a  layer  of  tan  about  two  inches  thick,  and  fills  the 
rest  of  the  eight  or  ten  inches  with  good  spent  tan, 
covers  this  with  boards  loaded  with  stones,  so  as  to  have 
a  certain  pressure;  for  as  soon  as  this  vat  is  wet,  the 
force  of  the  liquor  pressing  in  often  raises  up  the  whole. 
Let  the  calf-skins  remain  two  months  in  this  pit ;  at  the 
end  of  this  time  the  tan  is  spent,  and  the  process  of  tan¬ 
ning  will  not  go  on  if  they  remain  longer  in  this  pit. 
Now  take  them  out,  and  beat  them  with  switches,  in 
order  to  get  off  the  spent  tan  which  commonly  clings  to 
the  flesh  side.  After  this  the  skins  will  be  put  to  tan 
again  in  the  same  way,  but  on  the  other  side.  This 
time,  however,  less  is  used  than  the  first  time ;  the  work¬ 
man  presses  the  skins  together  as  hard  as  he  can,  and 


268 


TANNING. 


takes  especial  care  that  the  tail  part  of  the  skin,  and 
throat,  and  back  of  the  neck,  which  parts  most  resist 
the  influence  of  the  tanning  material  are  well  covered 
with  tan.  This  pit  is  weighted  and  wet  the  same  as 
the  first,  and  if  one  wish,  he  can  finish  them  up  in  forty- 
five  days,  but  it  is  better  to  let  them  stand  two  months. 


If  we  make  a  resume  of  the  time  of  the 
rations,  we  have  the  following : — 

various  ope 

D epilation,  including  river  work 

15  days. 

Three  vats  for  coloring  ..... 

30  “ 

Soaking  .  ..... 

15  “ 

Treatment  with  liquor  ..... 

30  “ 

First  pit  ...  ... 

60  “ 

Second  pit  ....... 

60  “ 

The  ivhole  ....... 

210  “ 

At  the  end  of  this  time  the  skins,  in  case  they  are 
not  treated  with  too  strong  ooze  in  the  first  and  second 
vats,  though  they  must  have  been  sufficiently  long  in 
the  third  coloring  vat,  and  likewise  in  the  soaking  pit, 
and  in  the  ooze  pit,  as  also  in  the  mixed  pit,  are  com¬ 
pletely  tanned,  and  ready  for  currying,  unless  they  have 
been  neglected  between  these  successive  operations,  and 
they  are  very  tender,  soft,  and  clean  from  grain. 

A  calf-skin  for  dressing  should  be  tanned  with  great 
care.  Should  you  leave  the  calf-skins  three  or  four 
months  in  every  pit,  and  neglect  to  lay  them  down  flat, 
or  to  put  them  carefully  in  pairs,  the  grain  side  within, 
they  would  become  hard.  The  grain  side  of  this  skin 
would  be  too  brittle  for  dressing  ;  the  nerve  of  the  skin 
would  be  brought  up  too  sharp,  and  it  would  be  impos¬ 
sible  for  the  dresser  to  make  a  soft  skin  of  it ;  blood 
vein  would  hinder  the  table  worker,  and  make  it  too 
hard  for  finishing  upon  the  table.  In  order  to  soften  it 
sufficiently  a  great  quantity  of  oil,  tallow,  and  degras 
must  be  employed ;  the  grain  side  will  assume  a  brown¬ 
ish  color  like  oiled  cowhide ;  and  when  this  grain  side 
is  compressed  it  will  tear  and  spring  upon  the  pressure  ; 
in  stretching  the  pushing  iron  will  stick  fast  in  the  tex¬ 
ture  of  the  substance  which  has  acquired  a  too  strong 
power  of  resistance,  and  the  workman  will  not  get  on  well. 


TANNING  OF  CALF-SKINS. 


269 


To  get  a  fine  and  good  dressing,  therefore,  the  calf¬ 
skin  must  be  well  filled  with  tanning  material,  but  only 
with  the  right  quantity.  If  it  is  too  little  tanned,  it  does 
not  take  up  the  particles  of  fatty  matters  which  are  sup¬ 
plied  for  it  in  dressing,  does  not  gain  in  weight,  for  it 
grows  then  too  much  in  finishing,  and  because  the  tex¬ 
ture  of  the  latter  is  not  sufficiently  saturated  with  the 
tanning  matter  it  becomes  fibrous  in  skinning.  Conse¬ 
quently  we  get  skins  that  are  flat  and  full  of  cavities 
upon  the  neck  pieces  and  upon  the  grain  side ;  even 
more,  we  obtain  a  grain  side  which,  in  eight  to  fifteen 
days  after  it  is  curried,  changes  its  color.  The  same 
thing  happens  if  they  are  too  strongly  saturated  with 
the  tanning  material;  they  remain  hard,  and  show  an 
enormous  weight. 

Seven  months’  tanning,  well  carried  on,  is  sufficient  for 
middling  calf-skins  of  from  twelve  to  fourteen  pounds 
without  head  ;  from  eight  to  ten  months  for  large  calf¬ 
skins  that  we  put  in  the  pit  a  third  time.  If  the  tanning 
is  extended  beyond  this  space  of  time,  provided,  always, 
that  the  operations  are  carried  on  in  proper  succession, 
little  cow-hides  are  produced,  and  consequently  a  bad 
material  for  dressing,  because  it  is  too  hard. 

A  good  currier  recognizes  all  these  wants  when  he  has 
to  dress  a  calf-skin  tanned  in  a  defective  manner.  By 
the  employment  of  great  carefulness  he  may  indeed  re. 
store  it  so  as  to  make  it  passable;  but  he  can  never  make 
from  it  a  skin  of  the  first  quality.  Therefore,  if  one  tans 
for  his  own  dressing  he  must  follow  the  simple  method 
which  we  lay  down  as  far  as  possible,  and  he  can  then 
be  sure  of  obtaining  magnificent  results. 

Dressing. — Have  the  calf-skins  taken  from  the  pits  in 
which  they  have  been  treated  the  second  or  third  time 
with  tan,  and  have  them  beaten  with  switches  to  clear  off 
the  tan  which  clings  to  the  flesh  side.  Then  have  them 
brought  up  upon  dry  ground  in  order  to  dry  them  in  the 
air.  In  great  manufactories  in  which  the  arrangements 
are  complete,  from  one  hundred  to  one  hundred  and  fifty 
skins  are  brought  under  a  hydraulic  press,  and  are  dried 
uniformly  in  a  moment.  By  this  much  hard  labor  is  saved, 


270 


TANNING. 


and  the  operation  answers  nearly  the  same  purpose  as 
drying  in  the  air;  it  is  to  be  preferred,  even,  because  the 
calf-skins  which  are  laid  out  to  dry  in  the  air  need  a  care¬ 
ful  watching  that  the  neck-piece  and  the  extremities 
may  have  the  same  degree  of  dryness  as  the  rest ;  neg¬ 
ligent  workmen  often  let  the  extremities  become  dry, 
and  then  moisten  them  up  again.  This  carelessness  in¬ 
jures  the  quality  of  the  parts  of  the  skin  dried  first. 
In  the  treatment  with  oil  it  happens  if  the  workman 
does  not  take  great  care,  that  the  oil  will  too  freely  pene¬ 
trate  those  parts  from  which  the  tanning  liquor  has  not 
been  evaporated  by  the  action  of  the  air;  great  atten¬ 
tion  must  be  paid  to  this  so  that  the  calf-skin  may  dry 
uniformly  in  all  its  parts.  When  the  calf-skins  have 
dried  in  the  air,  they  are  spread  out  and  then  stacked  up 
in  a  pile.  An  apprentice  takes  a  hard  brush  and  goes 
over  both  sides  of  every  skin  and  then  it  goes  into  the 
hands  of  the  currier. 


CHAPTER  XLVII. 

TANNING  OF  GOAT  AND  SHEEP-SKINS. 

Goat  and  sheep-skins  are  used  by  tanners  to  manufac¬ 
ture  morocco.  Owing  to  the  scarcity  of  goats,  the  tanners 
use  very  few  fresh  skins,  the  supply  being  drawn  from 
Switzerland,  Germany,  Africa,  the  East  Indies,  and  Asia 
Minor.  As  imported  they  are  dried  and  covered  with 
hair;  they  require  breaking  and  softening,  which  is  done 
by  soaking  them  several  days  in  water,  treading  them 
under  feet,  rinsing,  and  scraping  them  on  the  flesh  side 
to  produce  evenness.  They  are  then  passed  through 
three  old  lime  pits,  the  same  precautions  being  observed 
as  in  the  treatment  of  calf-skins.  The  process  is  con¬ 
tinued  until  the  hair  can  be  easily  detached,  which  gene¬ 
rally  requires  about  one  month,  then  scrape  them  on  the 
beam,  re-immerse  in  lime  milk  for  two  days,  and  flesh 
with  the  scraping  knife.  Goat-skins  require  more  rins¬ 
ing  than  others,  and  the  operation  must  be  repeated 
several  times  in  running  water.  Bait  the  unhaired  skins 


TANNING  OF  GOAT  AND  SHEEP-SKINS. 


271 


with  pigeon’s,  hen’s,  or  dog’s  dung,  to  remove  the  excess 
of  lime.  Sometimes  bran-water  is  used  as  bate. 

The  skins,  after  being  scraped,  are  sewed  into  bag 
form  with  the  grain  side  outward,  and  partly  filled  with 
a  strong  solution  of  sumach ;  inflate  them  by  the  breath, 
close  them  tightly  and  throw  them  into  a  vat  containing 
a  shallow  depth  of  weak  liquor  of  sumach,  and  make 
them  float  by  means  of  a  constant  agitation  so  as  to  as¬ 
sure  the  uniform  action  of  the  tanning  material  through 
the  surface  of  the  skin,  as  represented  below.  Leave  a 


Fig.  70. 


few  hours,  take  out  the  bags  and  pile  them  upon  each 
other  so  as  to  insure  the  uniform  action  of  the  tan  liquor 
through  the  pores  of  the  skin. 

Repeat  the  process  with  new  liquor,  then  unstitch  the 
bags,  rinse  and  scrape  them  on  the  beam,  and  suspend 
them  in  the  drying  loft.  These  crust  skins  are  moist¬ 
ened,  rubbed  out  smooth  with  a  copper  tool  upon  a 
sloping  board,  and  hung  up  to  dry  previous  to  coloring. 
By  this  process  a  goat-skin  can  be  dyed  in  one  day. 

Another  method  is  to  steep  the  skins  for  several  days 
in  a  fermenting  mixture  of  bran  water,  scrape  them  on 
the  beam,  soak  and  rinse  in  clear  water.  Lime  in  the 
usual  manner;  work  or  rub  them  over  with  a  tool  of 
hard  schist  to  press  out  the  lime ;  smooth  and  soften  the 
grain ;  full  them  by  agitation  in  a  revolving  cask,  lined 
inside  with  pegs,  and  containing  water. 

Tan  as  above,  two  lbs.  of  sumach  being  required  for  each 
hide.  The  French  process  is  the  same  as  the  above. 


272 


TANNING. 


This  method  constitutes  the  preparation  of  the  true 
morocco.  The  imitation  morocco  is  prepared  from  sheep¬ 
skins  in  the  same  manner  as  the  above,  except  that  after 
being  stripped  of  wool,  they  must  be  subjected  to  power¬ 
ful  hydrostatic  pressure  for  the  expulsion  of  oleaginous 
matters,  which  being  contained  in  a  large  amount  would 
otherwise  seriously  interfere  with  the  tanning. 

Lime  them  in  pits  containing  thirty-three  pounds  of 
lime  for  every  dozen  skins,  and  allow  them  to  remain 
from  three  weeks  to  a  month.  Then  deprive  them  of 
hair ;  resteep  them  in  the  pits  for  five  or  six  days;  rinse; 
beat  in  tubs,  and  when  perfectly  clean  desposit  them  in 
ooze  for  one  month. 

When  sheep-skins  are  tanned  for  common  leather, 
use  oak  bark  instead  of  sumach. 

The  color  is  imparted  in  the  same  manner  as  cloth  is 
dyed  by  means  of  a  mordant. 

Some  dye  the  skins  when  they  reach  the  state  prepar¬ 
atory  to  going  into  the  tan  liquor,  by  sewing  them 
together  with  the  grain  outwards;  then  mordanting,  and 
afterwards  giving  them  two  immersions  of  a  half-hour 
each  in  the  dye  bath. 

The  most  common  method  is  to  take  the  tanned  skins 
as  they  come  from  the  drying  loft ;  place  two  together, 
and  rub  them  exteriorly  with  a  brush  containing  the 
mordant  solution,  and  applying  the  color  afterwards  in 
the  same  manner.  When  the  dyeing  is  finished,  rinse, 
drain,  spread  out;  sponge  with  oil  to  preserve  the  flexi¬ 
bility,  and  send  to  the  currier. 

The  black  is  imparted  by  the  application  of  a  solution 
of  red  acetate  of  iron;  crimson ,  by  a  mordant  of  alum, 
or  tin  salt,  and  decoction  of  cochineal ;  puce ,  by  mordant 
of  alum  and  decoction  of  logwood;  blue ,  by  a  solution  of 
sulphate  of  indigo  ;  olive,  by  a  weak  solution  of  copperas 
as  a  mordant,  and  decoction  of  barberry,  containing  a 
little  of  the  blue  bath  as  coloring  liquor;  violet,  by  the 
consecutive  application  of  a  decoction  of  cochineal  and 
weak  indigo  bath. 

The  skiver  is  a  kind  of  leather  made  from  sheep-skins, 
split  while  in  the  state  of  pelt  by  machinery.  It  is 


TANNING  OF  GOAT  AND  SHEEP-SKINS. 


273 


tanned  by  sumach  in  vats,  being  spread  out  instead  of 
sewn  into  bag  form,  as  from  its  lesser  thickness  it  is 
more  readily  impregnated  with  the  tan  material. 

The  extreme  thinness  of  sheep-skins  renders  necessary 
a  peculiar  apparatus,  and  nice  manipulations  for  its  bisec- 

Fig.  U. 


tion.  The  above  figure  represents  a  splitting  machine, 
with  the  skin  undergoing  the  process  of  being  split. 

This  manipulation  presents  a  double  advantage ;  one 
skin  being  made  into  two  portions  which  are  then  re¬ 
spectively  adapted  to  uses,  for  which  the  original  skin, 
on  account  of  its  thickness,  was  not  suited.  The  vibrat¬ 
ing  knife  and  rollers  are  so  arranged  as  to  give  an  equal 
thickness  to  both  sections  of  the  skin,  or  a  greater  thick¬ 
ness  to  one  side  than  to  the  other,  as  may  be  desired. 
The  knife  acts  slowly,  but  completes  the  section  in  about 
two  minutes.  This  kind  of  leather  is  used  for  hat  linings, 
pocket-books,  box  covers,  &c. 

The  roan  is  sheep-skin  morocco,  tanned  with  sumach, 
but  wanting  the  grained  appearance  of  true  morocco, 
which  is  imparted  by  the  grooved  roller  in  the  finishing. 

Bleaching  of  Goat-skins. — Bleaching  goat-skins  in  win¬ 
ter,  by  natural  means,  is  a  difficult  and  tedious  opera¬ 
tion,  which  can  be  materially  shortened  by  the  employ- 
18 


274 


TANNING. 


ment  of  chemical  bleaching  means.  Sulphurous  acid  is 
usually  used  for  this  purpose,  hut  a  better  result  can  be 
obtained  by  the  careful  use  of  chloride  of  lime,  which 
being  sufficiently  diluted  and  completely  neutralized, 
will  bleach  skins  perfectly  in  two  days.  The  solution 
is  thus  prepared.  Treat  two  pounds  of  chloride  of  lime 
by  twenty  pounds  of  water;  let  stand  some  time,  stirring 
frequently;  when  the  liquid  has  become  quite  clear  mix 
with  it  two  and  a  half  pounds  of  glauber  salt  dissolved 
in  water.  Leave  to  settle;  decant  the  clear  liquor,  and 
lay  the  skins  in  until  entirely  bleached,  which  takes 
about  two  days.  Rinse  the  skins  well  in  water.  They 
could  be  softened  and  rendered  pliable  by  placing  them  in 
a  lukewarm  soap  bath,  both  prepared  from  white  soft  soap. 

Coloring  of  Whole  Sheep-skins. — At  the  first  indus¬ 
trial  exhibition  held  in  London  in  1851,  there  were 
exhibited  whole  sheep-skins  sent  from  various  places  and 
beautifully  and  durably  colored  in  the  principal  colors 
that  can  be  brought  out  on  wool,  and  a  path  has  been 
opened  to  their  nse  as  rugs,  carriage  mats,  and  many 
other  purposes,  where  such  soft  and  long-haired  sheep¬ 
skins,  dyed  to  present  a  handsome  appearance,  can  be 
used.  The  handsomest  specimens,  as  far  as  cleanness  and 
beauty  of  color  are  concerned,  were  undoubtedly  sent 
for  exhibition,  first  of  all  from  the  London  establish¬ 
ments,  and  then  from  Paris  and  Brussels  houses. 

The  mode  of  dyeing  the  skins  above  named  must  have 
been  a  special  coloring  method,  for  the  wood  showed  a 
uniform  color  even  to  the  hide,  and  was  at  the  same 
time  perfectly  firm.  The  method  of  stretching  the  skin 
and  then  brushing  it  over  with  hot  dye-stuff's,  a  mode 
that  furriers  now  and  then  follow,  conld  not  have  been 
employed  in  this  case,  as  such  can  be  easily  recognized; 
although  there  is  very  little  difficulty  in  dyeing  wool, 
there  is  a  great  deal  of  dyeing  entire  skins,  where  the 
hide,  the  leather  upon  which  the  single  wool  fibres  grow 
firmly,  cannot  stand  the  high  temperature  of  the  bath 
necessary  to  the  dyeing  process,  and  must  not  therefore 
be  placed  in  it. 

As  the  matter  was  one  of  general  interest,  efforts  were 


TANNING  OF  GOAT  AND  SHEEP-SKINS. 


275 


made  at  the  time  in  London  to  discover  the  mode  of 
operation,  which  was  kept  secret  in  some  degree,  and 
after  many  useless  attempts  the  whole  simple  method 
became  known. 

We  communicate  this  method,  although  twelve  years 
have  since  elapsed,  partly  because  these  whole  dyed 
sheep-skins  created  a  great  sensation  in  the  trade,  and 
yet  the  method  of  coloring  them  is  almost  unknown,  and 
again  because  the  question  is  brought  up  in  a  German 
paper,  which  copied  it  from  an  old  number  of  the  Muster 
Zeitung. 

Long-haired  sheep-skins,  having  the  hair  two,  three, 
or  four  inches  long,  are  usually  dressed  by  white  tanners 
and  farriers  by  the  ordinary  process,  then  cleansed  and 
brought  wet  to  be  dyed.  For  this  purpose  they  are 
stretched  upon  a  suitable  board  and  tacked  to  it  with 
small  nails,  the  flesh  side  downwards;  and  in  order  to 
make  them  adhere  well,  both  the  skin  and  the  board  are 
previously  wet,  thereby  securing  a  very  firm  and  uniform 
level.  The  board  is  provided  on  the  under  side  with 
transverse  pieces  which  prevent  it  from  warping  under 
the  dampness,  it  being  vitally  requisite  to  have  a  per¬ 
fectly  level  board.  Besides  this  the  four  corners  are 
furnished  with  rights  to  which  are  attached  four  slender 
chains  of  equal  length,  the  ends  of  which  come  together 
in  another  ring  at  the  centre  (as  in  a  weighing  scale, 
only  the  chains  are  shorter  in  proportion),  and  to  this 
central  ring  is  attached  another  chain  which  is  wound 
around  a  roller  or  pulley,  so  that  the  board  remains  in  a 
horizontal  position,  and  can  be  raised  or  lowered  at  will. 
After  the  skin  is  thus  stretched  the  wool  hands  down  on 
the  under  side.  T)his  is  the  preparation  for  dyeing. 

The  coloring  itself  is  done  in  flat  boxes  which  should 
be  larger  than  the  board  and  12  inches  in  depth.  They 
are  made  of  copper,  and  can  be  tinned  if  requisite,  and 
they  have  a  double  bottom  that  they  may  be  heated  by 
steam.  The  boxes  are  to  be  filled  with  water  mixed 
with  wool  refuse,  and  the  dye  stuff  according  to  the 
nature  of  the  color  to  be  produced.  The  dye-stuff  should 
be  quite  concentrated  in  order  that  the  hair  may  not 


276 


TANNING. 


remain  over  long  in  the  bath ;  then  the  vessel  should  be 
heated  by  steam  until  it  seethes,  that  is,  as  high  as  to 
avoid  the  bubblings  of  the  contents. 

The  pulley  above  referred  to  should  be  immediately 
over  the  vessel,  so  that  the  board  can  be  raised  or  low¬ 
ered  by  the  single  chain.  The  board  should  be  lowered 
at  the  surface  of  the  liquid  for  a  moment,  to  give  a  lus¬ 
tre  to  the  leather,  then  let  into  it  and  then  draw  out 
in  order  to  color  only  the  wool,  which  is  soon  accom¬ 
plished.  The  liquor  should  be  kept  hot,  not  in  a  state 
of  ebullition,  but  simmering  only;  and  the  water  turned 
into  3team  should  be  made  good  in  exact  proportion. 
After  the  color  develops  itself  rinse  and  dry  the  skins. 

Every  wool  dyer  can  employ  this  mode  of  coloring 
with  an  ordinary  kettle,  if  he  takes  care  to  observe  the 
main  points.  They  are  a  uniform  stretching  of  the 
skin,  a  horizontal  and  level  immersion  in  the  liquor,  a 
gently  simmering,  not  bubbling  color  bath,  made  rather 
strong,  and  a  restitution  of  the  water  changed  to  steam. 
The  leading  colors  are  deep  scarlet,  yellow,  green, 
bronze,  Saxony,  blue,  orange,  brown,  black,  etc. 


CHAPTER  XLYIII. 

MOROCCO  LEATHER  DRESSING— CORDOVAN  LEATHER. 

Morocco  Leather  Dressing. —  Although  enamel  oil 
cloth,  having  its  surface  finished  to  imitate  morocco 
leather,  has  come  into  very  extensive  use  during  the 
past  ten  years,  still  it  does  not  seem  to  have  injured  the 
manufacture  of  the  genuine  article.  Morocco  dressing 
establishments  are  still  increasing  in  number  and  ex¬ 
tent.  Real  morocco  leather  is  made  of  tanned  goat¬ 
skin,  but  the  term  is  now  applied  also  to  tanned  sheep¬ 
skin,  which  is  colored,  and  dressed  with  a  polished  and 
corded  surface  in  imitation  of  morocco.  The  manufac¬ 
ture  of  sheep-skin  into  colored  leather  is  carried  on 
extensively  in  Albany,  N.  Y.,  by  the  old  firm  of  A. 
Williamson  and  Sons.  In  this  establishment  colored 
sheep-skin  is  principally  used  for  shoe-bindings,  and  the 


MOROCCO  LEATHER  DRESSING. 


277 


majority  of  the  pelts  are  obtained  green  from  sheep  and 
lambs  slaughtered  in  the  vicinity.  About  100,000  skins 
are  dressed  annually,  and  from  this  about  half  a  million, 
pounds  of  wool  are  obtained  and  sold. 

The  first  process  through  which  they  are  made  to 
pass  is  that  of  soaking  and  softening  by  water,  to  fit 
them  to  receive  the  unhairing  preparation.  Formerly, 
hydrated  lime  was  sprinkled  in  the  inside  of  each  pelt ; 
it  was  then  folded  over  with  the  wool  side  out,  and  laid 
down  on  the  floor,  sometimes  called  the  pit.  In  this 
manner  a  whole  pile  or  heap  was  made,  and  a  heating 
action  was  engendered,  by  which  the  roots  of  the  wool 
were  loosened,  so  that  the  fleece  could  be  easily  pulled 
or  scraped  off  on  a  table  afterwards.  This  method  of 
loosening  the  roots  of  the  wool  was  tedious,  occupying 
several  days  to  complete,  and  the  skins  required  con¬ 
stant  watching,  as  they  were  liable  to  overheat  and 
injury,  both  to  the  wool  and  the  gelatinous  tissue.  This 
was  especially  the  case  in  warm  weather;  but  a  remedy 
for  this  trouble  and  these  ills  was  lately  introduced  by 
Mr.  Williamson,  and  is  one  of  the  most  important  im¬ 
provements  made  for  many  years  in  this  art.  This  is 
effected  by  a  calcined  orpiment  compound  which  they 
import.  It  is  made  up  into  a  thick  creamy  consistency ; 
then  applied  to  the  inside  of  the  skins,  which  are  folded 
over,  wool  side  out,  and  laid  in  a  heap.  In  twenty-four 
hours  the  skins  can  be  deprived  of  their  wool,  and  if 
they  have  to  lie  longer  no  injury  will  result.  In  all 
cases  the  depilatory  action  is  certain  without  injury  to 
wool  or  skin  tissue.* 

The  next  operation  is  that  of  washing  the  skins  prior 
to  unrolling  them.  This  latter  operation  is  executed 
by  placing  them  upon  an  inclined  bench,  and  rubbing 
off  the  wool  with  a  blunt  tool.  The  flesh  side  of  the 
skin  is  also  scraped  to  remove  slime  and  loose  flesh ; 
after  which  they  are  ready  for  the  liming  operation. 

*  By  referring  to  Chapter  XXVIII.,  the  reader  will  see  that  this 
so-called  improvement  was  a  process  known  for  a  long  time,  and  orpi¬ 
ment  and  lime  have  been  the  first  agents  fixed  for  the  depilation. 


278 


TANNING. 


They  are  now  placed  in  vats  containing  milk  of  lime,  in 
which  they  are  treated  for  about  two  weeks. 

The  next  operation  consists  in  passing  the  skins 
through  a  bath  of  hen  or  pigeon  manure,  mixed  with 
water,  which  softens  them.  After  this  they  are  washed, 
and  passed  through  a  bath  of  dilute  sulphuric  acid, 
which  neutralizes  all  the  lime  that  may  remain  in  the 
pores  of  the  skin.  After  this  they  are  dipped  into  a 
solution  of  common  salt ;  sewed  up  at  the  edges  with 
the  grain  side  out,  to  form  bags,  partly  filled  with  tan¬ 
ning  liquor,  inflated  and  tied.  They  are  now  placed  in 
a  tub  containing  an  extract  of  Sicily  sumach,  in  which 
they  float,  and  are  kept  in  constant  motion  for  several 
hours,  and  when  they  have  absorbed  a  sufficient  amount 
of  tannic  acid  they  are  taken  out,  drained,  and  rinsed ; 
and,  if  not  to  be  colored,  they  are  ripped  out,  and  dried 
in  the  atmosphere  in  sheds  constructed  for  this  purpose. 

They  are  stretched  on  boards,  rubbed  out  to  render 
them  smooth,  and  tacked  down,  so  as  to  dry  without 
wrinkling.  These  skins  are  generally  filled  three'times 
with  fresh  liquor  to  tan  them  fully. 

The  next  operation  is  that  of  coloring.  If  the  color 
is  to  be  applied  topically,  by  putting  it  on  the  surface 
with  a  sponge,  the  skins  are  first  dried.  If  they  are  to 
be  dyed  in  liquors  they  are  sewed,  so  as  to  have  the 
grain  side  out ;  then  mordanted,  and  afterwards  handled 
in  a  tub  containing  the  coloring  agents.  Prussian  blue 
color  is  imparted  by  handling  the  skins,  first  in  a  dilute 
solution  of  nitrate  of  iron  for  about  an  hour ;  then  in  a 
warm  bath  containing  yellow  prussiate  of  potash,  and  a 
little  sulphuric  acid.  A  beautiful  blue  is  thus  obtained. 
A  scarlet  is  prepared  with  a  mordant  of  chloride  of  tin 
and  cream  tartar;  the  red  color  is  afterwards  obtained 
by  handling  them  in  an  extract  liquor  of  cochineal ; 
purple  is  dyed  by  applying  a  cochineal  color  on  the  top 
of  a  Prussian  blue ;  bronze  is  obtained  from  a  strong 
extract  of  logwood  and  alum.  After  being  dyed  the 
skins  are  rinsed,  stretched  on  boards ;  rubbed  smoothly 
down;  tacked  around  their  edges,  and  dried. 

Topical  colors  are  given  to  the  grain  surfaces,  in  many 


MOROCCO  LEATHER  DRESSING. 


219 


instances;  they  simply  consist  of  a  strong  extract  ap¬ 
plied  with  a  sponge  on  a  piece  of  cotton  cloth ;  almost 
any  color  can  thus  be  put  on.  A  scarlet  color  is  made 
by  a  topical  application  of  an  extract  of  turmeric  upon 
a  dyed  cochineal  red.  '  To  enable  some  of  the  coloring 
agents  to  go  on  evenly,  milk  and  the  white  of  eggs  are 
frequently  mixed  with  them.  These  applications  also 
serve  to.  impart  a  metallic  lustre  to  the  surface.  Prior 
to  rolling,  the  dyed  skins  are  slightly  shaved  on  the 
wrong  side  and  trimmed  at  the  edges. 

The  subsequent  finishing  operations  consist  in  rolling 
the  skins  on  a  table  under  a  small  weighted  roller  hav¬ 
ing  a  grooved  face,  and  which  is  attached  to  a  suspended 
arm  which  the  operator  moves  back  and  forth  until  the 
roller  has  traversed  the  entire  surface.  This  operation 
imparts  a  glossy  Cordovan  surface  to  the  leather.  A 
second  rolling,  with  the  grooves  running  in  an  angular 
direction,  gives  the  surface  a  diamond  corded  finish,  the 
true  morocco  style.  Formerly  these  skins  were  all 
finished  by  hand  labor.  The  operatives  stretched  them 
on  inclined  boards,  and  rubbed  over  their  surface  with 
grooved  balls  of  ebony  held  in  the  hand.  Sometimes 
an  extra  finish  is  still  imparted  in  this  manner  to  skins. 

This  establishment  is  to  our  knowledge  the  first  which 
applied  (in  this  country)  aniline  dyes  on  leather.  The 
colors  thus  produced  are  magnificent.  However,  we  do 
not  recommend  them,  as  they  have  no  stability. 

Cordovan  Leather. — Cordovan  leather,  which  takes  its 
name  from  the  city  of  Cordova,  in  Spain,  and  of  which 
the  original  preparation  is  attributed  to  the  Moors,  is 
plain,  but  handsome,  with  a  fine  grain,  and  similar  to  the 
morocco  which  is  ordinarily  tanned  with  oak  bark,  nut 
galls,  or  sumach.  Jfihe  best  kinds,  especially  the  yellow 
Cordovans,  are  brought  from  the  Levant.  Those  of  Spain, 
France,  and  Hungary  are  also  highly  esteemed,  and  in 
Germany  the  cities  of  Dantzic,  Lubec,  and  Leipsic  en¬ 
joy  a  reputation  for  like  productions.  The  material 
used  in  the  manufacture  comprises  goatskins,  dog-skins, 
and  even  hog-skins  ;  they  are  produced  of  every  color  and 
quality,  but  those  made  from  the  goat-skins  are  the  best. 


280 


TANNING. 


The  skins,  after  having  been  cleaned  and  stretched  in 
water,  are  placed  in  lime  pits ;  they  are  then  replaced 
in  water  for  a  space  of  from  eight  to  fifteen  days,  care 
being  taken  to  renew  it  from  time  to  time,  and  to  work 
the  skins  by  treading  upon  them  with  the  feet.  After  a 
lapse  of  a  fortnight  a  bath  is  applied  composed  of  water 
and  dog’s  dung,  the  temperature  not  being  higher  than 
that  of  new-drawn  milk  ;  then  a  second  bath,  equally 
composed  of  water  and  of  wheat-bran.  Immediately  on 
being  taken  from  the  bath  the  skins  are  stretched, 
pressed  between  two  boards,  and  rubbed  with  kitchen 
salt.  They  are  then  immersed  in  a  third  bath  prepared 
of  figs  and  water.  Only  skins  which  it  is  intended  to 
color  black  are  dyed  after  having  been  tanned.  Black 
leather  is  tanned  in  liquor  of  the  extract  of  oak  bark; 
that  of  lighter  color  must  be  placed  in  an  ooze  made  up 
of  water  and  the  extracts  of  sumach  and  nutgalls. 

When  the  operation  of  tanning  is  completed,  the 
leather  should  be  withdrawn,  taking  with  it  as  little 
moisture  as  possible,  and  spread  in  the  shade,  where 
care  should  be  taken  to  rub  on  the  bloom  with  Sesam 
oil  before  the  sides  can  become  perfectly  dry.  After  the 
oil  is  laid  on,  the  process  of  drying  in  the  shade  may  be 
completed,  and  the  skin  may  be  folded  on  the  flesh  side. 
When  it  is  desired  to  give  to  the  Cordovan  a  rough  as¬ 
pect,  the  surface  may  be  rubbed  off  with  a  dull  knife 
immediately  after  spreading. 

In  many  parts  of  Southern  Russia,  particularly  at 
Ivaraszubazar,  a  city  of  the  Crimea,  of  which  the  Cordo¬ 
van  manufacturers  enjoy  a  high  reputation,  wormwood 
( artemisia  absinthium )  is  employed  to  make  fast  the  color 
in  the  leather.  If,  for  example,  it  is  proposed  to  dye 
the  leather  black,  a  decoction  of  wormwood  is  mixed 
with  pulverized  cochineal,  and  then  alum  is  added. 

In  the  island  of  Cyprus,  Cordovans  are  dyed  red  in 
the  following  manner:  The  skins,  generally  about  fifty 
at  a  time,  are  placed  in  a  fig  bath ;  they  are  then  passed 
into  a  strong  solution  of  alum  heated  to  a  temperature 
equivalent  to  that  of  fresh  milk ;  they  are  afterwards 
strung  up  on  poles  to  drip,  and  at  length  stretched,  in 


TANNING  OF  HORSE-HIDES. 


281 


order  to  expel  as  much  of  the  dampness  as  possible  ; 
finally,  the  skins  are  extended  on  a  table,  and  after  being 
uniformly  stretched  the  red  color  is  applied  with  a  cot¬ 
ton  rag.  The  coloring  matter  is  prepared  by  taking 
ground  cochineal,  and  boiling  it  in  soft  water  in  a  well- 
tinned  kettle,  and  during  the  ebullition  five  ounces  of 
powdered  alum  are  added  for  every  five  ounces  of  cochi¬ 
neal,  and  the  liquor  boils  until  it  has  been  reduced  one- 
sixth  or  one-eighth  by  evaporation,  when  it  is  poured 
through  a  filter.  The  skins  are  coated  four  or  five 
times  with  this  preparation,  and  after  being  placed  in 
the  tanning  liquor,  are  submitted  to  the  operation  of 
dressing. 

In  Hungary  and  in  Transylvania,  where  the  manu¬ 
facturers  of  Cordovan  produce  goods  which  are  highly 
esteemed  for  their  quality,  the  red  color  is  laid  on  in  a 
different  manner.  When  the  skins  have  been  properly 
prepared  for  the  process,  they  are  fastened  together  by 
couples  in  the  form  of  bags,  care  being  always  taken  to 
place  the  sides  to  be  colored  within  and  facing  each 
other,  and  to  leave  but  one  opening.  Into  this  opening 
the  warm  coloring  matter  is  poured  ;  the  mouth  of  the 
bag  is  then  tied,  and  if  the  color  does  not  readily  pene¬ 
trate  all  parts  of  the  skin  and  readily  unite  with  them, 
they  are  agitated  or  rolled  around. 


CHAPTER  X  L  I  X . 

TANNING  OF  HORSE-HIDES. 

About  sixty  years  ago  the  tanning  of  horse-hides  was 
considered  a  problem,  but  now  they  are  largely  converted 
into  leather,  and  they  make  excellent  material  for  uppers 
and  the  legs  of  boots. 

They  are  lined  in  the  same  way  as  calf-skins,  but  being 
much  thicker  they  require  a  longer  exposure  in  the  tan 
pits,  eight  months  being  necessary. 

Horse-hides  can  be  easily  tanned,  and  transformed  into 
excellent  leather  in  fifty  days,  by  the  following  process:* 


*  Dumas,  “  Traite  de  Chimie  Appliquee  aux  Arts.” 


282 


TANNING. 


“  Soak  the  skins  for  one  night,  and  pass  them  successively 
through  three  lime  pits ;  let  them  remain  one  day  in 
each,  the  fresh  pit  containing  one  bushel  of  lime  for 
seven  skins.  Take  out  and  wash  in  running  water ;  work 
them  in  the  usual  way  on  the  beam,  and  pass  them 
through  the  vats,  remaining  six,  eight,  and  in  winter, 
ten  days  in  the  first  one.  During  this  part  of  the  ope¬ 
ration  take  them  out,  and  replace  them  from  time  to 
time,  as  often  as  eight  or  ten  times  daily  for  the  first  five 
days.  The  liquid  of  the  first  vat  should  mark  0.7°  by 
Baume’s  areometer;  that  of  the  second  should  be  0.9°, 
and  while  in  this  the  skins  should  be  taken  out  only  once 
daily.  After  nine  or  ten  days,  remove  them  to  the  third 
liquid,  which  has  a  density  of  1.2  ;  allow  them  to  remain 
in  for  the  same  length  of  time  ;  and  finally  keep  them  for 
ten  or  twelve  days  in  the  last  vat,  which  marks  2°.  Dur¬ 
ing  this  last  period,  two  baskets  of  fresh  tan,  weighing 
55  lbs.,  should  be  daily  thrown  into  each  vat. 

“  After  removal  from  the  last  vat  the  skins  are  tho¬ 
roughly  tanned.  They  are  then  rubbed  upon  a  marble 
table,  first  on  the  flesh,  then  on  the  hair  sides  ;  half  dried 
upon  hooks  attached  to  the  ceiling  of  the  drying  room, 
and  sent  slightly  moist  to  the  currier. 

“A  horse-hide  weighing  22  lbs.  loses  6£  lbs.  by  clean¬ 
ing,  but  gains  lbs.  in  the  tanning.”  This  process  is 
very  simple,  but  requires  all  the  attention  and  care  of  the 
workmen,  and  differs  from  that  for  other  hides,  in  their 
not  being  placed  at  all  in  pits,  and  in  being  subjected  to 
the  action  of  tannin  while  floating  in  liquid. 

CHAPTER  L. 

TANNING  OF  DIFFERENT  SKINS. 

Tiie  skins  of  bucks,  wolves,  elks,  dogs,  and  other  ani¬ 
mals  can  be  tanned  as  those  of  goats  and  sheep.  Those 
of  lambs,  kids,  cats,  rabbits,  and  hares,  do  not  require 
exposure  to  as  strong  infusion,  nor  for  so  great  a  length 
of  time  as  sheep- skins,  while  those  of  hogs,  wild  boars, 
and  bears,  are  prepared  like  them.  When  these  skins 


TANNING  OF  THE  SKINS  OF  SHEEPS’  LEGS. 


283 


are  fresh,  and  when  it  is  intended  to  prepare  them  with 
the  hair,  the  time  is  considerably  lengthened.  Human 
skins  can  be  tanned  like  others.  They  have  more  body 
than  cow-skins,  and  are  thickest  upon  the  abdomen. 
They  require  a  greater  number  of  limings  and  of  expo¬ 
sures  to  the  infusions  of  bark,  and  they  swell  up  a  great 
deal  under  these  operations. 


CHAPTER  LI. 

TANNING  OF  THE  SKINS  OF  SHEEPS’  LEGS  FOR  MAKING 
TUBES  WITHOUT  SUTURE,  FOR  COVERING  THE  CYLIN¬ 
DERS  USED  IN  COTTON  AND  WOOL  SPINNING. 

A  Parisian  tanner,  M.  Delvau,  introduced  this  process, 
which  consists  in  cutting  the  skin  of  the  sheep’s  foot 
above  the  spur,  and  stripping  it  off  in  a  manner  similar 
to  that  after  which  rabbits  are  uncased.  This  tube  is 
then  limed,  until  the  wool  falls  off,  is  daubed  with  oil, 
and  curried  so  as  to  make  it  of  an  equal  thickness 
through. 

To  apply  these  tubes  to  the  cylinders  without  suture, 
two  burnishing  tools  are  used  for  spreading  them  out. 
Each  tube,  which  is  made  of  such  a  size  as  to  exceed 
the  cylinder  a  little  in  diameter,  is  drawn  over  it,  and 
stretched  upon  it  by  means  of  pincers,  and  the  parts 
which  pass  beyond  the  ends  of  the  cylinder  are  folded 
down,  smoothed  out,  and  glued  over  them.  These  extre¬ 
mities  are  then  rubbed  with  the  burnishers,  in  order  to 
make  the  glue  enter  the  substance  of  the  leather,  and 
they  are  left  to  dry  five  or  six  hours.  The  shreds  of 
leather  are  then  removed,  and  those  parts  which  project 
from  the  middle  and  ends  are  cut  away  on  a  turning 
lathe.  To  finish  the  surface  and  give  it  lustre,  it  is 
well  rubbed  with  a  hard  linen  cloth. 

Leather  Bottles. — These  bottles  are  used  in  France  to 
carry  oil  and  wine.  Cow-skins  are  used  for  this  pur¬ 
pose.  They  are  dried  upon  pegs  by  the  butchers,  and 
are  then  softened  in  lime  which  has  been  previously 
used,  and  in  which  they  remain  for  eight  days.  Then 


284 


TANNING. 


they  are  thrown  into  a  fresh  lime  pit  until  the  hair  readily 
comes  off;  they  are  cleaned,  rinsed,  and  fleshed  after 
having  been  cut  into  pieces  of  the  proper  shape.  Then 
expose  them  to  dry  upon  a  smooth,  clean  and  dry  spot 
of  ground,  great  care  being  observecj  that  this  drying 
takes  place  uniformly  and  gradually.  When  thus  de¬ 
prived  of  moisture,  and  at  the  same  time  preserving  all 
their  suppleness,  they  are  hung  up  for  a  month,  and  ex¬ 
posed  to  the  direct  rays  of  the  sun,  being  taken  down 
and  stored  at  night,  so  that  no  moisture  shall  have  access 
to  them. 

Before  being  sewed  they  are  placed  in  water  to  allow 
the  stretches  to  be  made.  These  bottles  last  a  long  time, 
but  liquids  kept  in  them  always  acquire  an  unpleasant 
taste. 


CHAPTER  LIT. 

EEC  LEATHER. 

The  butts  used  to  manufacture  this  kind  of  leather  are 
imported  from  Buenos  Ayres.  Soak  them  from  four  to 
five  days,  deposit  them  in  an  old  lime  vat,  extend  them 
evenly  so  they  may  not  wrinkle;  the  largest  hides  being 
cut  in  half  along  the  line  from  head  to  tail.  Handle 
repeatedly  in  this  pit  for  five  days,  and  deposit  them  in 
a  fresh  vat  where  they  remain  for  two  or  three  months; 
handle  them  twice  a  week,  and  add  a  little  fresh  lime 
during  each  of  the  last  five  handlings.  When  they  are 
ready  to  be  fleshed,  take  them  out,  rinse  them  four  times 
only  partially,  so  that  the  lime  may  not  be  entirely 
washed  out. 

Place  the  hides  in  the  pit,  and  stratify  them  with  the 
bark  of  the  root  of  the  evergreen  or  scarlet  oak,  which 
has  been  soaked  in  water. 

Leave  three  months  in  the  first  pit,  place  in  a  second 
one,  and  expose  them  to  the  action  of  the  bark  for  the 
same  length  of  time,  take  them  out,  dry  and  carry 
them  to  the  currier.  Each  hide  requires  about  120  lbs. 
of  bark. 


CHEMICAL  THEORY  OF  TANNING. 


285 


CHAPTER  L  1 1 1 . 

DANISH  PROCESS. 

By  this  process  dressing  leather  may  be  made  in  two 
months. 

Soak  the  hides,  flesh  and  free  them  from  hair,  and 
rinse  them  in  the  ordinary  manner;  color  them  like 
barleyed  skins.  Sew  them  into  form  of  bags,  leaving  an 
aperture  about  ten  inches  long,  by  which  you  fill  them 
with  tan  and  water.  Sew  those  openings,  and  beat  the 
closed  sacks  in  every  part,  for  the  purpose  of  distributing 
their  contents  equally  through;  then  deposit  them  in 
pits  containing  sufficient  ooze  to  completely  cover  them. 
These  pits  are  Tj  feet  in  depth;  the  same  in  breadth, 
and  from  Si  to  10 i  feet  long.  Place  upon  the  skins 
planks  heavily  loaded  with  weights,  and  press  them 
towards  the  bottom  to  increase  the  penetrating  power 
of  the  infusion.  To  have  them  equally  tanned,  remove 
the  boards  three  or  four  times  a  week,  beat  the  sacks 
and  change  their  position. 

These  skins  are  supple  and  pliable,  have  a  finer  color 
than  strong  leather;  they  are  thinner  than  those  made 
by  the  ordinary  process,  owing  to  their  not  swelling  up 
by  the  slow  process  of  feeding,  and  to  the  pressure  to 
which  they  have  been  submitted.  It  is  doubtful  if  the 
durability  and  other  qualities  of  the  product  are  equal 
to  those  of  leather  prepared  by  more  tedious  processes. 


CHAPTER  LI  V. 

CHEMICAL  THEORY  OF  TANNING. 

The  operation  by  which  skins  are  converted  into 
leather  has  been  known  and  practised  since  the  most 
remote  antiquity;  but  the  nature  of  the  tanning  prin¬ 
ciple  was  unknown  before  the  experiments  of  Lewis  and 
Deyeux,  and  the  experience  of  Seguin.  This  latter 
chemist  has  given  the  following  theory  of  the  art  of 
tanning; — 


286 


TANNING. 


1st.  The  skin  stripped  of  its  flesh,  is  a  substance  which 
can  be  easily  converted  by  a  convenient  process  into  an 
animal  jelly  which,  concentrated  and  dried  in  the  air, 
furnishes  glue. 

2d.  A  solution  of  this  latter  substance  being  mixed 
with  an  infusion  of  tan,  an  insoluble  precipitate  is  formed, 
and  this  precipitate  is  not  susceptible  of  putrefaction. 

3d.  The  solution  of  tan  is  composed  of  two  distinct 
substances,  one  precipitates  the  glue,  and  is  the  true 
tanning  matter,  the  other  precipitates  the  photo-sulphate 
of  iron  without  precipitating  the  solution  of  glue,  and 
produces  only  the  disoxygenation  of  the  skin  and  of  the 
substance  which  unites  the  hair  to  the  skin.* 

4.  The  operation  of  tanning  is  not  a  simple  combi¬ 
nation  of  the  skin  with  the  principle  which  precipitates 
the  glue,  but  a  combination  with  the  skin  disoxygenized 
by  the  substance,  which,  in  dissolution  in  the  tan  has 
the  property  of  precipitating  the  sulphate  of  iron.  Thus 
all  substances  to  be  used  to  tan  ought  to  have  the  pro¬ 
perties  of  precipitating  glue  and  sulphate  of  iron. 

5th,  The  operation  of  tanning  consists,  first,  in  the 
swelling  of  the  skins  by  an  acid  principle.  Second,  a 
disoxygenation  by  gallic  acid.  Third,  in  disoxygenating 
the  skin  with  the  same  principle,  and  by  this  disoxy¬ 
genation  it  is  in  a  middle  state  between  glue  and  skin. 
Fourth,  in  combining  it  by  this  disoxygenation. 

Whatever  are  the  merits  of  Seguin,  and  the  services 
be  has  rendered,  we  cannot  but  expose  all  the  errors  of 
the  above  theory. 

We  persist  in  looking  at  the  swelling  of  the  skin  as 
an  effect  less  chemical  than  mechanical,  which  is  princi¬ 
pally  due  to  the  interposition  of  the  water,  or  to  the 
effect  of  the  caloric  produced  by  the  fermentation.  Acids 
and  alkalies,  as  we  have  said,  act  only  as  a  means  of 
preserving  the  skin  from  putrefaction  ;  afterwards  they 
exercise  a  chemical  action.  Thus  the  lime  with  which 
the  interior  of  the  skin  is  saturated,  notwithstanding  all 

*  Seguin  does  not  speak  of  the  extractive,  which,  according  to  Sir 
H.  Davy,  is  necessary  to  form  a  flexible  and  firm  leather. 


CHEMICAL  THEORY  OF  TANNING 


287 


the  washings,  forms  with  the  tannin  a  tannate  of  lime, 
which  takes  away  the  suppleness  of  the  leather;  and  for 
this  reason  it  is  that  the  lime  method  is  injurious.  It  is 
not  the  same  with  acids.  Besides  preserving  the  skin 
from  putrefaction,  the  produced  acetic  acid  reacts  on  the 
fibrin,  softens  it  and  transforms  it  partly  into  a  trans¬ 
parent  jelly,  soluble  in  boiling  water  and  combining 
with  the  tannin.  Besides  this  acid,  by  which  the  skin 
is  more  or  less  saturated,  it  precipitates  the  solution  of 
tannin  and  fixes  a  larger  quantity  in  the  leather.  This 
softening  renders  the  swelling  very  easy.  However,  it 
can  be  operated  without  these  means,  which  are  in 
antagonism  with  Seguin’s  theory. 

We  do  not  agree  with  Seguin  that  gallic  acid  is  the 
principal  and  indispensable  agent  in  tanning.  No  ex¬ 
periment  has  demonstrated  the  durable  disoxygenation 
which  he  asserts,  and  which  is  impossible  if  we  compare 
the  respective  constituents  of  gelatine  and  fibrin.  Thus 

Fibrin  contains  .  19.615  per  cent,  of  Oxygen. 

Gelatine  “  .  72.207  “  “  “ 

From  this  we  see  it  is  impossible  that  gallic  acid  dis- 
oxygenizes  the  fibrin  and  transforms  it  into  glue,  whilst 
pure  gelatine  contains  nearly  one-third  more  of  oxygen. 
If  such  were  the  case,  gallic  acid  must  ozidize  instead  of 
disoxygenizing  it.  We  therefore  see  that  this  theory  is 
inadmissible.  Let  us  now  record  the  experiment : — 


Catechu  contains  from 

42  to  54  per  cent,  of  Tannin. 

Tea  “  “ 

84  “  40 

Herb  Bennett  “ 

42  “  “  << 

Scille  “ 

24  <<  “  << 

These  substances,  so  rich  in  tannin,  are  applied  with 
success  in  tanning,  while,  however,  they  do  not  contain 
a  particle  of  gallic  acid.  Seguin  does  not  mention  the 
extractive,  however ;  this  substance  has  some  action  in 
the  tanning,  and  according  to  the  experiments  of  Sir  H. 
Davy  its  presence  is  necessary  to  form  a  flexible  and 
firm  leather,  and  in  some  way  it  may  take  the  place  of 
tannin.  In  England,  where  tanning  material  is  very 
scarce,  they  have  used  the  decoction  of  cicuta;  and 


288 


TANNING. 


Schwerger  has  shown  by  analysis  that  100  parts  of  fresh 
leaves  contain  2.73  of  extractive  without  tannin  or 
gallic  acid. 

To  resume,  we  regard  tanning  as  a  combination  of  five 
principles,  fibrin ,  gelatine ,  tannin ,  extractive ,  and  acid. 

1st.  Gelatine  and  fibrin  are  transformed  into  a  jelly 
by  acetic  acid  with  tannin,  extractive  and  gallic  acid. 

2d.  In  tanning,  the  epidermis  disappears,  and  no  por¬ 
tions  of  the  skin  have  been  disoxygenized. 

3d.  The  action  of  gallic  acid  is  similar  to  that  of 
acetic  acid,  and  its  presence  is  not  necessary  in  the  ope¬ 
ration. 

4th.  Extractive,  like  tannin,  unites  with  the  altered 
gelatine  and  fibrin,  and  renders  leather  flexible  and 
firm.  It  is  also  the  principle  of  their  coloration ;  thus 
leather  tanned  with  gall  is  pale,  that  with  oak  bark  is 
brownish,  with  catechu  is  reddish,  etc.  It  is  the  ex¬ 
tractive  which  gives  to  the  leather  a  brownish  color, 
without  rendering  it  insoluble  in  boiling  water. 

5th.  Lime  forms  with  tannin  a  tannate  of  lime,  which 
destroys  the  suppleness  of  leather,  and  renders  it  dry  and 
brittle. 

6th.  Dried  skins  well  tanned  increase  in  weight  about 
33  per  cent.  This  increase  is  due  to  the  fixation  of  the 
tannin,  extractives,  gallic  acid  and  a  little  water. 

7th.  In  saturated  infusions  there  is  less  extractive  than 
tannin,  while  in  weak  infusions  the  extractive  predomi¬ 
nates.  That  is  the  reason  why  it  is  necessary  to  place 
the  skins  at  first  in  very  weak  infusions,  and,  lastly,  to 
saturate  them,  little  by  little,  with  tannic  acid  and  ex¬ 
tractive,  so  as  to  have  a  complete  tanning  and  a  more 
supple  leather. 

8th.  By  presenting  to  the  skins  strong  infusions,  the 
leather  contains  but  very  little  extractive,  and  is  tanned 
only  on  two  surfaces,  the  centre  containing  little,  so  that 
the  leather  obtained  is  hard  and  brittle. 

9th.  At  last,  gallic  acid  exercises  so  slight  an  in¬ 
fluence  on  tanning,  that  Sir  H.  Davy  thinks  it  is  doubt¬ 
ful  if  oak  bark  contains  any. 


CHEMICAL  THEORY  OF  TANNING. 


289 


Chemical  Researches  on  the  Art  of  Tanning  A  By  M. 
Knapp. — Every  one  knows  that  it  is*  not  the  skin  which 
is  worked  by  tanners,  but  the  prepared  skin,  or  the 
corium ,  or  the  skin  separated,  as  much  as  possible,  from 
the  useless  parts  by  mechanical  and  chemical  treatment. 

The  prepared  skin,  when  damp,  has  the  appearance 
of  a  tissue  of  a  milky  color  ;  seen  by  the  microscope  it 
appears  to  be  composed  of  parallel  fibres  without  color, 
and  transparent. 

The  transparency  and  the  milky  appearance  are  the 
effects  of  the  dispersion  of  light.  The  skin,  by  drying, 
contracts,  assumes  a  homogeneous  appearance,  and  be¬ 
comes  horned.  But  by  working  it  it  becomes  again  white 
and  pliable,  as  before  the  desiccation. 

This  change  of  nature  is  due  to  this,  when  the  skin 
dries,  the  fibres  which  compose  it  agglutinate,  one  on 
the  other,  exactly  as  the  surfaces  of  the  intestinal  skin, 
which  composes  violin  strings ;  thus  the  spaces  which 
separate  them  disappear,  and  it  no  longer  transmits 
light. 

The  object  of  tanning  is  at  first  to  destroy,  as  much 
as  possible,  the  tendency  of  the  skin  to  putrefy  princi¬ 
pally,  and  it  is  its  characteristic  function  to  cause  the 
skin,  when  dry,  to  remain  a  fibrous  tissue  without  trans¬ 
parency,  and  to  remain  pliable.  Three  operations  are 
necessary  to  transform  the  skin  into  leather,  the  anterior 
preparation ,  the  tanning ,  and  carrying. 

The  Preparation  consists  in  taking  out  the  flower  of 
the  epidermis,  and  the  hair  which  covers  it,  and  the  flesh 
of  the  adhering  membranes.  The  maceration  and  the 
working  are  sufficient  to  prepare  the  flesh  ;  the  treatment 
of  the  flower  requires  chemical  substances,  such  as  lime, 
sulphurets,  etc. 

The  modus  operandi  of  these  two  substances  is  different. 
Lime  acts  by  rendering  the  tissue  of  the  epidermis  softer, 
which  admits  of  its  easy  depilation,  whilst,  on  the  con¬ 
trary,  sulphurets  act  on  the  basis  of  the  hair,  render  it 
milky,  so  that  if  a  piece  of  skin  is  macerated  in  this  re- 


19 


*  Repertoire  de  Chimie. 


290 


TANNING. 


agent,  the  hair  can  be  taken  out  only  by  rubbing  it  with 
a  piece  of  wood. 

Tanning  is  generally  considered  as  a  chemical  opera¬ 
tion. 

Every  one  agrees  that  there  is  found  in  the  skin  an 
immediate  principle,  which  combines  with  the  tannin 
or  with  tanning  substances,  and  then  it  is  compared  to 
gelatine;  some  even  consider  the  leather  as  a  tannate  of 
gelatine. 

The  known  facts  are  sufficient  to  demonstrate  how  far 
this  theory  is  from  the  truth. 

At  first,  acidulated  bones,  which  give  gelatine  as  the 
skin,  are  not  capable  of  giving  a  product  similar  to  lea¬ 
ther,  whatever  is  the  quantity  of  tannin  and  the  time  of 
contact.  Then  the  salts  of  iron  and  alumina,  which  tan 
leather,  do  not  precipitate  the  gelatine.  At  last,  grease, 
which  tans  perfectly  well,  has  no  similarity  to  tannin. 

It  may  also  be  said  that,  generally,  when  a  chemical 
combination  takes  place,  the  former  disappears ;  and  it 
is  sure  that,  in  tanning,  not  only  the  texture  of  the  skin 
does  not  disappear,  but  is  rather  developed;  however, 
as  in  gun-cotton,  it  will  be  admitted  that  the  substance 
of  the  skin  can  combine,  without  apparent  change,  with 
the  tannin,  as  the  cotton  with  the  nitric  acid. 

A  more  serious  objection  is  in  the  known  fact,  that 
tanning  substances,  such  as  alum,  can  be  taken  from  the 
skin  by  a  sufficiently  long  washing ,  then  the  skin  reappears 
with  its  primitive  character. 

Tannin  itself  can  be  taken  from  the  skin.  If  we  take 
a  skin  which  has  been  immersed  in  pure  tannin  and  is 
transformed  into  leather ,  we  can,  by  a  weak  alkaline 
solution,  separate  all  the  tannin,  and  the  skin  can  be 
tanned  again.  However,  skin  which  has  been  tanned 
with  tan ,  and  treated  by  carbonate  of  soda,  loses  the 
greater  part  of  the  tannin  it  contains,  but  it  does  not 
cease  to  be  leather ,  as  is  the  case  with  skin  tanned  with 
pure  tannin.  It  retains  a  tanning  substance,  peculiar  to 
the  tan  and  differing  from  pure  tannin,  which  the  car¬ 
bonate  of  soda  cannot  dissolve.  Evidently  these  facts 
do  not  agree  with  the  theory  which  sees  in  tannin  a 


CHEMICAL  THEORY  OF  TANNING. 


291 


chemical  action.  Mr.  Knapp  thinks  that  analytical  ex¬ 
periments  alone  can  resolve  this  question.  For  this  pur¬ 
pose  he  takes  a  prepared  and  purified  skin,  dries  it  in 
vacuo,  and  operates  on  a  determined  weight  that  he  sub¬ 
mits  to  the  action  of  tanning  dissolutions,  and  weighs 
anew  after  a  thorough  washing  and  drying  in  vacuum. 
These  experiments  have  given  the  following  results. 

Skin  immersed  in  a  solution  of  alum  contained,  after 
the  operation,  8.5  per  cent,  of  additional  matter.  The 
increase  of  weight  was  due  only  to  the  incorporation  of 
the  alum  in  nature ;  there  is  no  chemical  decomposition 
in  this  operation.  With  sulphate  of  alumina  the  result 
was  the  same;  the  skin  fixed  27.9  per  cent,  of  anhydrous 
sulphate  of  alumina.  The  chloride  of  aluminum  acted 
in  the  same  manner ;  it  united  without  decomposition, 
and  the  skin  contained  29.3  per  cent.  Acetate  of  alu¬ 
mina  gave  the  same  results,  and  the  skin  contained  23 
per  cent,  of  this  salt. 

It  results  from  these  facts,  that  not  only  is  it  no  de¬ 
composition  of  the  tanning  salt,  as  in  acid  and  basic  salt, 
as  Berzelius  thought ;  but  that  the  quantities  absorbed 
are  without  relation  to  their  equivalents.  The  author 
adds  that  these  numbers  are  not  absolute ;  that  they  vary 
with  circumstances,  principally  with  the  concentration 
of  the  liquids,  and  that  the  fixed  salt  can  be  taken  out 
by  washing  with  pure  water.  Thus  the  proportion  of 
chloride  of  alumina,  after  a  washing  of  three  days,  has 
been  reduced  from  29.3  per  cent,  to  3  per  cent. 

The  corresponding  compounds  of  chrome  and  iron 
behave  in  the  same  manner  as  the  salts  of  alumina,  only 
they  are  absorbed  in  less  quantity,  and  they  color  the 
skin,  while  the  salts  of  alumina  do  not. 

Fatty  bodies,  as  sesquioxide  salts,  will  tan.  This  fact 
alone  is  in  opposition  to  the  idea  of  a  chemical  combina¬ 
tion  of  the  tanning  matter  with  the  skin.  Nevertheless, 
the  author  has  tried  to  prove  by  experiment,  if  there 
was  in  the  quantity  of  the  bodies  absorbed  to  convert 
the  skin  into  leather,  any  evidence  in  favor  of  the  theory 
which  he  was  disputing.  He  dipped  skins  into  alcoholic 
solutions  of  stearic  and  oleic  acid;  or  ethereal  solutions 


292 


TANNING. 


of  fish  oils,  and  he  ascertained  that  the  tanning  was  per¬ 
fect ,  and  that  the  fatty  body  was  not  modified,  and  the 
absorbed  quantity  was  from  1  to  H  per  cent.  Resins 
have  acted  like  greases.  This  small  quantity  of  tanning 
substance  represents  only  the  proportion  kept  in  solu¬ 
tion  by  the  reagent  in  which  the  skin  is  macerated. 

All  the  above  experiments  demonstrate  that  tanning 
is  not  a  chemical  action,  and  Mr.  Knapp  has  substituted 
for  the  old  theory  a  more  solid  one.  To  this  chemist, 
tanning  substances  have  the  function  of  enveloping  the 
fibres  of  the  skin,  so  that  their  adherence  becomes  im¬ 
possible,  and  that  the  skin  keeps  its  pliable  qualities 
after  the  desiccation,  or  at  least  recovers  it  by  a  mecha¬ 
nical  action;  this  is  to  him  the  true  character  of  tan¬ 
ning.  To  demonstrate  his  proposition,  he  established  a 
series  of  experiments,  the  object  of  which  was  to  tan 
the  skin  without  the  use  of  tanning  substances.  Consider¬ 
ing  that  the  fibres  agglutinate  together  only  when  they 
are  penetrated  by  water,  he  conceived  the  idea  of  putting 
the  skin  in  contact  with  a  liquid  (alcohol  or  ether)  which, 
expelling  the  water  by  endosmose,  takes  away  from  the 
fibres  that  property  of  agglutinating  together.  Accord¬ 
ing  to  his  views,  he  has  obtained  by  the  action  of  alcohol 
alone ,  a  tanned  skin  very  white  and  of  such  a  constitu¬ 
tion  that  practical  men  have  recognized  it  as  a  tanned 
skin.  Then  this  is  a  true  leather  without  tanning  matter , 
which  in  water  becomes  again  skin,  and  by  the  coction 
is  changed  into  glue. 

This  last  experiment  shows  that  tanning  is  not  a 
chemical  action.  When  Mr.  Knapp  speaks  of  tanning, 
he  understands  only  the  conversion  of  the  skins ,  which  in 
drying  ivill  become  horned ,  into  a  matter  which  remains 
flexible  even  by  desiccation.  For  the  other  qualities  that 
leather  requires  in  tanning,  such  as  imputrescibility, 
etc.,  they  are  not  absolutely  inherent  in  the  nature  of 
the  leather ;  they  are  only  relative,  and  they  are  ob¬ 
tained  at  variable  degrees  according  to  the  products 
obtained,  and  the  operations  to  which  the  skin  is  sub¬ 
mitted. 

The  conclusions  of  Mr.  Knapp’s  experiments  are  the 


CHEMICAL  THEORY  OF  TANNING. 


293 


following :  Tanning  is  not  a  chemical  operation,  leather 
is  no  more  tannate  of  gelatine  than  tanned  skin  is  a 
combination  of  gelatine  with  a  sub-sulphate  of  alumina. 

The  proof  of  it  is  in  the  following  facts :  Some  sub¬ 
stances,  which,  like  skins,  can  be  converted  into  glue, 
do  not  give  leather. 

Tanning  substances  are  not  absorbed  by  the  skin  in 
definite  proportions.  The  different  tanning  salts  do  not 
unite  with  the  skin  in  equivalent  proportions. 

Tanning  salts,  and  tannin  itself,  can,  by  washing,  be 
separated  from  the  leather,  which  becomes  skin  again. 

Fatty  bodies  which  have  no  similarity  to  astringent 
compounds,  will  tan  leather. 

Skins  may  acquire  the  properties  which  are  given  by 
tanning  without  the  use  of  tanning  compounds. 

At  last  some  substances  unite  with  the  skin  and  ren¬ 
der  it  imputrescible,  and  incapable  of  forming  gelatine  ; 
without  giving  it  the  qualities  of  leather. 

According  to  Mr.  Knapp,  leather  differs  from  the  dry 
skin  in  this,  that  in  the  last  the  fibres  adhere  one  to  the 
other,  while  in  the  first  they  are  isolated  ;  the  part  of 
the  tanning  substance  is  to  maintain  this  isolation. 

The  tanning  substances  surround  each  fibre  instead  of 
uniting  with  it  as  chemical  substances. 

To  realize  an  industrial  tanning,  you  want  reagents 
which  can  be  fixed  on  the  fibres  of  the  skin,  prevent 
the  adhering  of  these  fibres,  operate  with  rapidity,  and 
give  to  the  skin  the  required  suppleness  and  the  pro¬ 
perty  of  resisting  putrefaction.  These  conditions  are 
partly  fulfilled  by  the  use  of  salts  of  sesquioxide. 

The  tanning  action  of  iron  salts  has  been  known  for 
a  long  time,  but  it  has  not  been  much  utilized  yet. 

Leather  tanned  with  iron  salts  is  often  flat,  hard,  and 
brittle,  even  when  the  solutions  are  the  most  nearly  neu¬ 
tral  possible.  The  acid  reaction  of  the  salt  is  sufficient 
to  destroy  the  quality  of  the  leather.  It  is  a  known  fact 
that  an  alkaline  reaction  is  favorable  to  the  swelling  of 
skins. 

The  above  experiments  have  conducted  Mr.  Knapp 
to  the  following  process : — 


294 


TANNING. 


Prepare  two  baths,  one  with  soap-water,  the  other 
with  a  solution  of  iron,  alumina,  or  chrome. 

The  solution  of  soap  must  not  contain  more  than 
one-twentieth  or  one-thirtieth  of  soap.  If  hard  soap  is 
used  (soft  soap  is  better),  the  bath  is  kept  at  100°. 

Prepare  also  the  solution  of  tanning-salt,  which  should 
be  one-tenth,  with  the  chloride  of  iron,  which  colors  the 
skin  brown  red,  or  with  the  chloride  of  chrome,  which 
gives  a  gray-blue  color,  or  with  the  chloride  of  alumina, 
which  is  colorless. 

Dip  the  skins  in  the  metallic  solutions,  stir  them, 
draw  them,  dip  them  again,  and  so  forth,  till  they  are 
well  penetrated.  Forty-eight  hours  are  sufficient  to 
obtain  this  result. 

The  skins,  being  well  drained,  are  thrown  into  the 
solution  of  soap.  When  the  reaction  is  complete,  wash 
and  dry  them. 

This  operation  is  very  rapid,  and  it  may  be  rendered 
more  so  by  substituting  alcoholic  for  aqueous  solutions. 

We  see  that  this  process,  while  very  different  from 
tanning,  conducts  to  the  same  results ;  is  quicker  and 
cheaper,  and  gives  a  simpler,  brighter,  and  softer  skin. 

Tanning  can  also  be  obtained  by  dipping  the  skin  in 
a  very  weak  acidulated  water,  then  in  soap  water,  and 
repeating  this  operation  two  or  three  times  till  all  the 
skin  is  tanned.  Wash  and  dry. 

In  the  course  of  this  paper  we  have  spoken  of  an  ex¬ 
periment  consisting  in  impregnating  the  skin  with  an 
alcoholic  solution  of  stearic  acid.  The  author  insists  on 
that  experiment  as  giving  a  new  and  quick  process  of 
preparation.  Leather  thus  obtained  is  very  flexible,  and 
as  white  as  white  kid  leather;  the  grain  is  fresher  and 
brighter. 


seguin’s  process. 


295 


SECTION  VI. 

IMPROVED  PROCESSES. 

In  order  not  to  interrupt  the  series  of  the  operations 
of  tanning  we  think  it  better  to  devote  a  special  section 
to  the  improved  processes.  We  shall  make  no  comment, 
and  we  leave  it  to  intelligent  manufacturers  to  consider 
as  our  judgment  of  the  different  processes  we  describe 
that  which  agrees  with  what  we  have  before  expressed. 

CHAPTER  LV. 

SEUUIN’S  PROCESS. 

The  preliminary  processes  are  the  same  as  those  of 
others,  excepting  that  after  soaking  and  fleshing,  he 
rinses  the  skins  in  running  water,  so  as  to  expose  all 
parts  to  it.  He  depilates  them  with  lime  and  deposits 
them  in  tan  juice  mixed  with  or  sometimes  -joVo 
part  of  sulphuric  acid. 

For  raising,  he  uses  a  vat  lined  with  cement  contain¬ 
ing  lime  and  filled  with  water  containing  y-gVo-  Part  °f 
sulphuric  acid,  but  he  finds  that  the  acid  instead  of 
mixing  with  water  combines  with  the  lime.  For  these 
vats  he  substitutes  wooden  tubs  and  fills  them  with 
water  containing  -jitoo  part  sulphuric  acid,  which 
increases  to  yo^E,  ar*d  by  this  arrangement  he  was  ena¬ 
bled  to  raise  skins  in  forty-eight  hours.  According  to 
this  chemist  this  raising  is  not  necessary,  as  he  could 
make  excellent  leather  from  skins  not  submitted  to  this 
treatment. 

He  placed  the  skins  in  vats  filled  with  ooze.  To  ob¬ 
tain  this  solution  he  filled  a  number  of  tubs,  placed  in 
a  row,  with  ground  tan.  In  each  tub  he  put  a  certain 
quantity  of  water,  which  filtered  through  the  tan,  dis¬ 
solved  in  soluble  particles,  and  was  received  in  vessels 
beneath.  He  passed  the  liquid  of  the  first  vat  on  the 
second,  and  so  on  till  the  liquid  was  completely  satu- 


296 


TANNING. 


rated.  As  the  two  still  contained  a  certain  amount  of 
soluble  material,  he  treated  the  tubs  until  the  tan  was 
completely  exhausted. 

The  skins  being  taken  from  the  acid  bath,  he  placed 
them  in  a  very  weak  infusion  of  tan  and  allowed  them 
to  remain  only  one  or  two  hours  to  color  the  hair 
sides.  He  then  immersed  them  in  a  stronger  solution, 
and  continued  thus,  increasing  each  time  the  strength 
of  the  solution  until  the  tanning  was  completed. 


CHAPTER  LVI. 

PROCESS  OF  PREPARING  GLOSSED  LEATHER  BEFORE  THE 
TANNING  OPERATION. 

This  new  process  of  preparation  of  hides,  invented 
by  Messrs.  Monier  and  Ray,  consists  in  trampling  them 
in  a  fulling  machine,  disposed  so  as  to  contain  any 
liquid  put  in,  and  having  below  holes  for  the  water  to 
run  off. 

Details  of  the  TV ork  of  Preparation  of  the  Leather. 

Hides.— Soak  them  48  hours  in  cold  water. 

Smelting .- — Introduce  the  hides  into  the  fulling  ma¬ 
chine,  which  according  to  the  size  of  the  hide  will 
contain  8  or  10  or  even  16  of  them.  Trample  them 
for  half  an  hour,  which  is  sufficient  to  render  them 
sufficiently  supple. 

Liming. — After  beating  them  a  few  minutes  to  free 
them  from  water,  put  them  into  the  lime  vat,  the  lime 
being  of  the  consistency  of  thick  milk,  and  in  sufficient 
quantity.  The  hides  being  thus  exposed,  beat  them  for 
four  hours,  withdraw  them,  pile  them  one  upon  another, 
leave  them  for  five  days,  the  time  necessary  to  warm 
them,  and  then  put  them  back  into  the  fulling  machine 
to  clean  them. 

Cleaning.— Work  them  in  the  fulling  machine  for  1| 
hour,  take  them  out  and  scrape  them  well.  The  first 
cleaning  not  being  sufficient  to  take  off  all  the  lime, 
leave  them  one  hour  in  a  water  containing  jfa  of  sul- 


PROCESS  OF  PREPARING  GLOSSED  LEATHER. 


297 


phuric  acid,  handling  often.  Wash  them  well  in  running 
water. 


Description  of  Apparatus. 
Fig.  12. 


Front  view. 


298 


TANNING. 


Fig.  74. 


(a) .  Trough  in  which  the  skins  are  placed. 

( b ) .  Post  raised  above  the  trough,  and  supporting  the  levers  (c)  near 
their  upper  end,  where  these  levers  are  attached  to  a  piece  of  wood  ( d ). 

( e ).  Key  to  press  the  post  ( b )  and  to  give  it  the  necessary  inclination. 

(/).  Mallets  fixed  to  the  lower  end  of  the  levers  (c),  and  working 
on  the  skins,  in  the  hollow  part  of  the  trough  (a)  formed  by  the  curved 
line  seen  in  (g). 

(h) .  Keys  disposed  so  as  to  keep  the  mallets  conveniently  inclined 
to  the  form  of  the  curve  <7  of  the  trough. 

(i) .  Other  keys  having  the  same  uses  as  the  above. 

(k).  Two  curved  posts,  raising  above  the  trough  and  preventing  the 
mallets  from  swaying. 

(/).  Piece  of  wood  joining  the  posts  k  at  their  upper  extremity. 

( m ).  Vertical  turnstile  with  four  branches,  the  axis  (n)  of  which  is 
received  and  turns  in  the  posts  k,  and  is  used  as  a  shaft  to  the  ropes 
(0)  which  keep  the  mallets  suspended. 

(/>).  Wheel  put  in  motion  by  water,  its  axis  ( q )  carries  cams  ( r ), 
which  by  turning  let  the  mallets  (/)  rise  and  fall  alternately. 

Tanning.-—  After  the  cleaning  of  the  hides,  and  before 
putting  them  in  the  tan  vats,  they  are  submitted  to 
the  action  of  an  ordinary  press,  then  they  are  placed 
in  vats  filled  with  tan  water,  in  which  they  are  left  for 
six  days. 

After  six  days  the  leather  is  pressed  again,  and  is  put 
back  in  the  vats  containing  tan  water  stronger  than  the 
above.  It  is  left  in  for  ten  days.  Press  again  and  carry 
to  the  pits,  where  the  leather  is  left  two  or  three  months. 


TANNING  WITH  GRAPE-SKINS. 


299 


CHAPTER  L  V  II. 

TANNING  WITH  MYRTLE  ( Vaccinium  Myrtilus). 

This  process  was  discovered  by  a  tanner  of  Bern- 
Cassel,  Mr.  Rapenius,  who  found  that  a  superior  leather 
could  be  made  by  tanning  with  the  myrtle  plant.  This 
plant  is  collected  in  the  spring  of  the  year,  is  dried  and 
ground.  One  hundred  pounds  of  leather  require  three 
hundred  and  fifty  parts  of  this  substance,  while  it  requires 
six  hundred  parts  of  oak  bark,  and  its  use  saves  four 
months  of  the  time  generally  employed.  Leather  made 
with  it  is  of  a  superior  quality.  Shoes  made  with  it  last 
two  months  longer  than  those  made  from  common 
leather.  The  skin  of  the  neck  becomes  as  strong  and 
elastic  as  other  parts  when  thus  prepared.  The  myrtle 
should  be  cut  off,  and  not  pulled  up  by  the  roots.  After 
it  is  cut  it  is  not  injured  by  water  as  oak  bark,  which 
loses  by  exposure  to  moisture. 

CHAPTER  L  V 1 1 1. 

TANNING  WITH  GRAPE-SKINS. 

In  1829,  a  chemist  of  Narbonne  proposed  to  substitute 
grape-stalks  for  oak  bark  in  tanning.  His  process  is 
thus  spoken  of  by  Nachette,  in  the  Journal  of  Pharmacy. 

“A  substitute  for  oak  bark  has  long  been  sought  for, 
but  no  one  yet  has  before  thought  of  employing  for  this 
purpose  the  stalks  and  skins  of  the  grape.  This  chemist 
prepared  skins  for  tanning  by  the  ordinary  process; 
he  placed  them  in  vats  filled  with  stalks  and  skins  of 
grapes  (previously  distilled  to  save  the  alcohol) ;  he 
allowed  them  to  remain  from  thirty-five  to  forty-five 
days,  which  time  he  found  sufficient.  The  advantages 
of  this  process  are  the  following;  1st.  Less  time  is  re¬ 
quired.  2d.  A  refuse  material  of  some  localities  is  sub¬ 
stituted  for  the  expensive  oak  bark.  3d.  The  leather 
produced  has  a  slightly  agreeable  odor.  4th.  The  leather 
obtained  by  this  process  lasts  twice  as  long  as  that  ob¬ 
tained  by  the  ordinary  process.” 


300 


TANNING. 


CHAPTER  LIX. 

TANNING  WITH  STATICB  ( Marsh  Rosemary). 

This  process  was  discovered  by  Mr.  Tournal,  and  we 
give  below  the  full  details,  extracted  from  a  paper  writ¬ 
ten  by  him  on  the  subject. 

Mr.  Gayraud  and  himself  commenced  an  experiment 
with  an  ox-hide,  while  another  tanner,  M.  Mallaret, 
undertook  to  prepare  some  goat-skins.  Mr.  Gayraud 
prepared  the  hide  in  the  same  manner  as  with  the  bark 
of  the  root  of  the  kermes-oak,  except  that  he  divided  it 
into  two  equal  portions ;  one  he  tanned  with  the  statice 
and  the  other  with  the  root  of  the  kermes-oak,  in  order 
to  determine  what  difference  in  weight  would  be  pro¬ 
duced  by  the  two  materials. 

Six  months  had  passed  when  the  heat  of  the  weather 
produced,  in  the  statice  liquid,  so  active  a  fermentation 
that  it  burst  the  vessel  containing  it,  so  the  experiment 
could  be  carried  no  further.  The  tannin  had  penetrated 
nearly  to  the  centre,  and  probably  two  months  more  of 
exposure  would  have  completed  the  process.  The  leather, 
examined  by  good  judges,  was  declared  of  the  very  best 
quality.  Mr.  Mallaret  declared  that  goat-skins  tanned 
by  this  process  were  superior  to  that  with  oak  bark. 

M.  Tournal,  in  one  year,  tanned  perfectly  a  piece  of 
thick  Buenos  Ayres  hide,  which  in  the  ordinary  way 
would  have  required  eighteen  months. 

M.  Gayraud  then  commenced  the  tanning  of  more 
than  100  hors*fe-hides  and  50  imported  cow-hides,  while 
M.  Mallaret  tried  150  goat-skins,  and  M.  J.  Calas,  80 
horse-hides,  the  cow-skins  being  intended  for  soles,  the 
horse-hides  and  goat-skins  for  upper  leather. 

M.  Gayraud  placed  the  cow-skins  in  the  lime  pit, 
to  depilate  and  rise  them.  The  lime  revealed  many  de¬ 
fects  and  injuries,  so  that  out  of  the  fifty  hides,  one-third 
were  more  or  less  damaged,  and  some  had  to  be  trimmed 
to  one- half  their  size  in  consequence  of  being  injured. 
This  prevented  ascertaining  the  difference  in  weights  in 


leprieur’s  tanning  process. 


301 


the  process,  but  it  was  found  that  the  hides  were  tanned 
in  a  third* less  than  the  usual  time.  They  were  remark¬ 
able  for  weight,  beauty,  color,  and  strength.  The  same 
operator  weighed  exactly  a  certain  number  of  perfect 
skins ;  he  tanned  them  by  the  statice,  and  obtained  the 
most  satisfactory  results. 

In  the  preparation  of  horse-hides,  the  superiority  of 
statice  as  tan  was  evident  in  the  finer  structure  of  the 
product,  shortness  of  the  process,  economy  of  material, 
beauty  of  color,  increased  weight,  power  of  absorbing 
fatty  bodies,  etc.  The  same  advantages  were  perceived 
in  goat  leather. 

All  the  skins  thus  prepared  have  been  sold,  and  work¬ 
men  who  used  them  preferred  them  to  those  tanned 
by  the  usual  process.  They  equal  skins  tanned  with 
kermes-oak  bark  for  wear  in  damp  weather,  while  in  dry 
weather  they  are  much  superior.  As  to  flexibility,  they 
hold  thread  better,  and  are  more  easily  worked.  The 
leather  for  uppers  is  remarkable  for  suppleness  and  firm¬ 
ness,  and  for  the  brilliancy,  intensity,  and  durability  of 
the  black  color  which  can  be  given  to  it. 

CHAPTER  LX. 

LEPRIEUR’S  TANNING  PROCESS. 

Four  operations,  about  similar  to  those  followed  by 
tanners,  constitute  Leprieur’s  process. 

1.  The  rinsing ,  comprising  the  softening  of  dry  hides, 
washing,  swelling,  etc. 

2.  The  sugar  of  lead  hath. 

3.  The  tan  liquor  hath. 

4.  Tanning. 

A.  SUGAR  OF  LEAD  BATH. 

This  operation  comprises  the  following  manipulation : 
1st,  the  hides  being  well  washed  and  drained  are  put 
into  the  bath  ten  to  twelve  hours  in  summer,  and  24  to 
30  in  winter.  This  bath  is  thus  prepared : — 

Acetate  of  lead  (sugar  of  lead)  .  .  1  lb. 

Water  .......  125  galls. 


302 


TANNING. 


Such  a  bath  is  sufficient  for  6  to  8  hides. 

It  is  to  the  precipitate  formed  by  this  salt  and  the 
albumen  that  the  author  attributes  the  solidity  of  the 
leather,  which  is  neither  hollow  nor  brittle.  When  out 
of  this  bath  put  it  in  another  prepared  in  the  same  pro¬ 
portions,  being  careful  in  the  two  immersions  to  stir  the 
hides  every  three  or  four  hours.  After  remaining  12 
to  24  hours  in  this  bath,  wash  carefully  in  running 
water. 


B.  TAN  LIQUOR  BATHS. 

The  author  contends  that  the  raising  is  not  an  essen¬ 
tial  condition  for  tanning,  and  if  necessary  it  can  be 
obtained  by  adding  acid  in  the  first  infusions ;  he  gives 
the  proportion  of  1  part  of  tan  for  10  parts  of  dry  hides, 
with  enough  sulphuric  acid  to  impart  a  decided  acid 
taste,  as  being  all-sufficient  for  the  purpose. 

First  Series  of  Infusions. 

First  Bath. — This  bath  for  every  110  lbs.  of  hides  is 
composed  of  22  lbs.  of  tan  ;  infuse  the  hides  for  24  hours 
in  enough  water  to  cover,  but  not  completely  sink  them. 
To  this  mixture  add  from  91  to  91  ounces  of  sulphuric 
acid  at  66°  B.  If  after  a  maceration  of  24  hours  the 
liquid  is  not  sensibly  acid,  add  some  more,  if  it  is  desired 
to  raise  by  it. 

In  summer  keep  the  hides  in  this  bath  30  or  40  hours, 
for  after  that  time  it  will  putrefy.  In  winter  they  may 
remain  one  day  longer. 

Second  Bath. — For  110  lbs.  of  hides  use  33  lbs.  of  tan 
and  acidify  this  bath  as  the  above.  Keep  the  skins  in 
for  36  hours,  take  them  out  to  drain,  immerse  them  30 
hours  more,  and  drain  again.  This  bath  is  no  longer 
serviceable  except  as  a  putrid  ferment  for  new  infusions. 

Third  Bath. — For  110  lbs.  of  skins  use  44  lbs.  of  tan, 
and  add  9|  ounces  of  sulphuric  acid,  if  the  previous 
raising  has  been  considered  sufficient.  Take  out  the 
skins  by  intervals,  wash  in  water,  drain  and  replace.  If 
after  a  stay  in  the  bath  of  four  or  five  days  it  shows  3° 
or  4°  by  the  acid  hydrometer,  allow  the  skins  to  remain 


leprieur’s  tanning  process. 


303 


24  hours  longer,  or  better,  the  liquid  may  be  used  in  the 
same  manner  as  the  first  bath  for  thin  skins. 

Fourth  Bath.— Operate  as  above,  using  55  lbs.  of  tan, 
and  leaving  the  skins  in  it  for  six  or  eight  days.  The 
skins  before  being  placed  in  the  vat  are  drained  for  eight 
or  twelve  hours,  and  are  taken  out  at  least  three  times 
to  ascertain  that  the  liquor  has  not  become  too  weak. 
If  the  degree  shown  by  the  acid  hydrometer  is  four  or  five 
tenths,  prepare  a  fresh  liquid  and  reserve  the  old  one  for 
skins  which  are  undergoing  the  second  series  of  baths. 
According  to  Leprieur,  it  is  better  to  deposit  fresh  skins 
in  old  baths  which  they  quickly  exhaust,  than  in  those 
more  advanced. 

Second  Series  of  Infusions. 

First  Bath. — According  to  Leprieur  a  new  set  of  skins 
begins  with  the  fourth  bath  of  the  first  series  of  infusions, 
and  require  330  lbs.  of  bark  to  tan  them  as  completely 
as  the  others. 

Second  Bath. — Since  the  fifth  bath  of  the  first  series 
would  not  be  disposed  of  in  time  to  answer  for  the  second 
bath  of  the  second  series,  and  would  moreover  be  too 
strong,  a  new  one  should  be  prepared  like  that  of  No. 
2.  After  the  fourth  hath  stratify  the  leather  and  tan, 
alternately  interposing  willow  twigs  so  that  the  surfaces 
be  equally  soaked. 

First  Series. — Fifth  Bath. — For  110  lbs.  of  hides  use 
66  lbs.  of  tan.  Keep  the  hides  in  the  vats  6  to  8  days, 
take  out,  draw,  and  replace  three  or  four  times  during 
this  period.  If  strips  of  wood  are  placed  between  them, 
it  will  be  sufficient  to  cover  the  last  layer  of  tan  with  the 
infusion  to  the  height  of  half  an  inch. 

Second  Series. — Third  Bath. — The  fifth  bath  forms  the 
third  of  the  second  series. 

Sixth  Bath. — To  110  lbs.  of  hides  use  66  lbs.  of  tan, 
leave  10  days,  take  out  and  drain  at  intervals  of  two  or 
three  days.  When  the  infusion  marks  more  than  5  or 
6  of  the  acid  hydrometer,  take  the  skins  out,  and  the 
bath  is  reserved  for  others  which  are  less  advanced  in 
preparation. 


304 


TANNING. 


Fourth  Bath. — The  fifth  bath  like  the  sixth,  not  being 
unoccupied  soon  enough  to  answer  for  the  fourth  of  the 
second  series,  it  is  necessary  to  prepare  it  with  fresh 
materials,  like  No.  4.  It  is  then  the  sixth  of  the  first 
series  under  the  denomination  five. 

Fifth  Bath. — The  hides  can  remain  in  this  bath  until 
the  fifth  bath  of  the  first  series  is  fully  prepared;  there 
is  then  no  more  danger  of  the  putrefaction  of  the  hides. 

Seventh  Bath. — For  110  lbs.  of  hide  use  88  lbs.  of 
bark.  Leave  the  hides  to  remain  twelve  or  fifteen  days, 
or  until  the  liquid  marks  no  more  than  from  six  to  seven 
by  the  hydrometer.  After  that  time  it  will  serve  for 
the  second  set  of  skins.  When  the  hides  are  taken  from 
this  bath  and  cut,  the  section  shows  a  well-tanned  sur¬ 
face,  while  the  inside  is  unchanged.  The  operation  has 
taken  nearly  fifty  days,  and  every  110  lbs.  of  hides  have 
consumed  385  lbs.  of  bark.  Supposing  that  1100  lbs. 
of  tan  are  used  to  tan  that  weight  of  leather  by  the 
ordinary  method,  there  still  remain  717  lbs.  to  be  used 
in  the  pits  to  make  the  expenditure  the  same. 

Sixth  Bath. — The  seventh  bath  of  the  first  series  is 
the  sixth  of  the  second ;  but  it  is  a  matter  of  indifference 
whether  the  hides  are  at  once  deposited  in  the  vats,  or 
again  exposed  to  a  bath  of  110  lbs.  of  tan  to  an  equal 
weight  of  leather. 

C.  TANNING  IN  THE  VATS. 

Leprieur  uses  tan  well  mixed  with  water,  to  which 
he  adds  sulphuric  acid  in  the  same  proportions  as  above 
indicated.  Upon  the  bottom  of  the  vat  he  deposits  a 
layer  of  this  mixture;  he  spreads  a  hide  upon  it,  and 
he  continues  the  stratification  until  the  vat  is  filled. 
The  last  hide  is  covered  with  a  stratum  of  one  inch  of 
the  mixture;  he  throws  in  a  quantity  of  water  sufficient 
to  rise  above  the  surface,  and  covers  the  whole  with 
weighted  boards  to  prevent  the  skins  from  floating.  The 
liquid  of  the  vat  is  tested  every  three  or  four  days  with 
the  hydrometer,  to  ascertain  if  any  diminution  of  strength 
has  taken  place.  In  this  case  the  skins  are  taken  out, 
and  deposited  in  another  vat.  Taking  into  consideration 


leprieur’s  tanning  process. 


305 


that  110  lbs.  of  good  tan  give  1320  lbs.  of  infusion 
marking  1°  of  strength  by  the  hydrometer,  and  10°  or 
12°  of  the  acid  hydrometer  after  forty-eight  hours,  it 
will  be  easy  to  ascertain,  day  by  day,  from  the  diminu¬ 
tion  of  density,  how  much  of  the  tanning  principle  has 
been  absorbed.  When  the  infusion  has  lost  one-half  of 
its  strength  it  will  still  serve  for  other  processes,  and 
another  supply  of  tan  is  given. 

First  Tanning  in  Vats. 

For  the  first  vat  use  one  hundred  parts  of  tan  for  one 
hundred  parts  of  hides,  the  water  being  mixed  as  before 
with  a  little  more  than  nine  ounces  of  sulphuric  acid. 
Leave  the  skins  in  this  first  vat,  twelve  to  fifteen  days, 
and  besides  testing  the  liquor  by  the  hydrometer,  the 
skins  should  be  cut  from  time  to  time,  to  ascertain  the 
progress  of  the  tanning.  If  considerably  advanced,  and 
if  the  liquid  is  reduced  to  five  or  six-tenths,  the  vat 
should  be  changed. 

Second  Series. — The  contents  of  the  first  vat  are  not 
exhausted,  but  furnish  a  strong  infusion  for  a  sixth  bath 
for  the  second  set  of  skins. 

Second  Tanning  in  the  Vat. 

Expose  100  parts  of  skins  with  120  parts  of  tan,  for 
fifteen  days. 

First  Tanning. — The  preceding  or  second  tanning  of 
the  first  series  forms  the  first  tanning  of  the  second 
series.  The  skins  taken  from  the  first  tanning  are  then 
exposed  to  the  second. 

Third  Tanning. — Expose  100  parts  of  hides  with  130 
parts  of  bark,  from  fifteen  to  twenty  days ;  the  prepa¬ 
ration  is  the  same  as  before.  Examine  carefully  the 
hides,  as  probably  the  thinnest  ones  are  tanned. 

Fourth  Tanning. — This  is  the  second  of  the  second 
series.  Use  140  parts  of  tan  for  100  of  hides;  expose 
from  fifteen  to  twenty  days. 

Third  Tanning. — The  preceding,  or  the  fourth  of  the 
first  series,  serves  as  the  third  of  the  second  series. 

Fifth  Tanning. — Use  160  parts  of  tan  for  100  parts 

20 


306 


TANNING. 


of  hides ;  expose  from  twenty  to  thirty  days.  This 
quantity  of  176  lbs.  completing  the  1100  lbs.,  used  for 
the  first  series. 

Fourth  Tanning. — This  is  the  fifth  of  the  first  series. 

If  after  twenty  days  the  tanning  is  not  completed, 
from  fifteen  to  twenty  days  more  may  he  allowed  to 
elapse  before  the  leather  is  taken  out ;  this  being  the 
last  tanning. 

If  it  should  be  necessary  to  ttdd  220  lbs.  more  of  tan 
to  the  amount  already  used,  220  lbs.  of  leather  would  be 
completely  tanned  by  means  of  1650  lbs.  of  bark. 

Quantities  of  Tan  Employed  for  Tanning  220  lbs.  of 


Leather. 

First  Series. 

Tan  for  baths 
“  “  pits 

Second  Series. 

.  385) 

.  716j 

1101 

Tan  for  baths 

.  881 

264 

“  “  pits 

.  176) 

1365 

According  to  the  author : — - 

Strong  and  supple  hides  are  tanned  in  from  100  to  130 
days. 

Middling  ones  in  about  150  days. 

Refractory  ones  in  about  180  days. 

Sometimes  a  sixth  tanning  is  required,  which  does  not 
much  increase  the  duration  or  expense  of  the  prepa¬ 
ration. 


CHAPTER  LX I. 

D’ARC'ET’S  PROCESS  BY  THE  SULPHATE  OF  SESQUIOXIDE 

OF  IRON. 

According  to  this  author,  this  process  is  simple  and 
economical,  the  time  of  working  it  short,  the  price  of 
the  material  very  low,  and  it  seems  at  first  that  this 
process  is  to  be  preferred  to  any  other. 

A  solution  of  sulphate  of  peroxide  of  iron  poured  in 


newton’s  process. 


307 


a  solution  of  gelatine  or  albumen  produced  an  abundant 
precipitate  similar  to  that  obtained  with  tannin;  thus  a 
skin  dipped  in  a  solution  of  sulphate  of  sesquioxide  of 
iron  can  be  perfectly  tanned.  It  had  some  inconveni¬ 
ences  :  it  is  that  some  free  sulphuric  acid  was  left  free 
in  the  leather,  and  the  other  was  that  salts  of  iron  dis¬ 
organize  the  leather.  Boucherie  has  seen  that  by  intro¬ 
ducing  linseed  oil,  this  last  inconvenience  was  removed. 
The  destructive  action  of  sulphuric  acid  can  be  avoided, 
as  wre  have  seen,  by  dipping  the  leather  in  a  weak  solu¬ 
tion  of  soap.  This  process  is  very  short ;  four  days  are 
sufficient  for  thin  skins  and  eight  days  for  thick  ones. 
We  have  no  doubt  this  is  an  advantageous  process,  and 
before  rejecting  it  we  must  wait  for  the  results  of  the 
experiment  on  a  large  scale. 


CHAPTER  LX  1 1. 

NEWTON’S  PROCESS. 

This  method  is  an  accelerating  process  combining  the 
use  of  mineral  and  vegetable  substances.  It  consists  in 
the  employment  of  certain  earthy  alkaline  or  metallic 
salts  for  the  preliminary  treatment  and  of  an  astringent 
for  the  tanning.  This  joint  action  promotes  the  combi¬ 
nation  of  the  albuminous  matter  of  the  skin  with  the 
bases.  When  other  material  than  catechu  is  used,  the 
latter  of  good  quality  and  containing  50  per  cent,  of 
tannin  is  taken  as  standard  for  regulating  the  proportion 


of  the  former. 

The  skins  must  be  unhaired  and  free 

from  lime. 

FOR  100  CALF-SKINS. 

Take : 

Alum 

.  .  .  .  .  .  20  lbs. 

Salt 

. 10  “ 

Catechu  . 

. 100  “ 

Sulphate  of  alumina  ....  4  “ 


This  latter  can  be  used  either  alone  or  mixed  with  2 
lbs.  of  common  salt.  The  three  mixtures  are  dissolved 
in  water  and  kept  apart  in  separate  vessels. 


308 


TANNING. 


In  a  vat  place  one-fifth  of  the  first  solution,  one-tenth 
of  the  second,  and  one-fourth  of  the  third;  immerse  the 
skins  in  this  liquor,  handle  and  stir  them  repeatedly  for 
a  short  time,  then  take  them  out.  Then  refresh  the  vat 
by  the  addition  of  one-fiftli  of  the  first  solution,  one- 
tenth  of  the  second,  and  one-fourth  of  the  third.  Re¬ 
place  the  skins  in  this  mixture,  treat  as  before,  but  a 
longer  time.  Remove  the  skins  a  second  time,  refresh 
the  vat  with  one-fifth  of  the  first  solution,  one-tenth  of 
the  second,  reimmerse  as  above.  Let  them  remain  some 
time,  handle  occasionally,  remove  again,  and  mix  in  the 
vat  the  residues  of  the  first  and  third  solutions  and  one- 
fifth  of  the  second.  Put  back  the  skins  a  few  days  after, 
take  them  out  to  add  to  the  vat  the  remaining  two-fifths 
of  the  second  mixture ;  four  or  five  weeks  are  sufficient 
to  complete  the  tanning. 

This  process  may  be  modified  by  laying  the  skins  in 
a  vat  and  stratifying  them  with  3  lbs.  of  moistened  tan. 
Other  skins  can  be  thus  tanned,  but  the  proportions  vary 


we  could  see  below. 

One  hundred  goat-shins  require — 

Alum  ...... 

10  to  12  lbs. 

Catechu  ...... 

50  to  60  “ 

Salt . 

6 

One  hundred  cow-hides  require — 

Sulphate  of  alumina  .... 

2  to  300  lbs. 

Salt  ...... 

100 

Catechu  ...... 

500 

One  hundred  and  ninety  ox-liides  require — 

Sulphate  of  alumina  .... 

14  to  16  lbs. 

Salt . 

8 

Catechu  ...... 

60  to  70  “ 

CHAPTER  L  X 1 1 1. 

PREPARING  DRY  FLINT  HIDES. 

As  a  green  hide  becomes  dry  by  evaporation  of  its 
liquid,  the  flesh  side  absorbs  oxygen  from  the  atmo¬ 
sphere  which,  combining  with  the  fresh  fibro-gelatinous 


PREPARING  DRY  FLINT  HIDES. 


309 


surface  forms  a  hard,  flinty  scale.  To  free  the  hide  from 
the  scale  and  facilitate  its  softening,  tanners  submit  it  to 
hard  beam  breaking,  or  to  the  action  of  a  hide-mill,  both 
of  which  have  the  detrimental  effect  to  some  extent  of 
disturbing  the  uniform  relations  of  the  interposed  gela¬ 
tine  and  loosening  the  small  bundles  of  fibres  composing 
the  structure  of  the  hide,  thereby  weakening  the  hide 
in  its  textile  strength,  nor  have  any  of  the  modern  soaks 
proved  less  detrimental,  depending  as  they  do  upon  a 
putrefactive  condition.  The  first  effect  of  such  soak  is 
to  decompose  the  parts  of  the  hides  easiest  affected,  gen¬ 
erally  the  fibro-gelatinous  structure,  immediately  beneath 
the  scale;  hence  the  frequent  water  peltings  and  running 
of  hides  in  the  soak,  particularly  in  warm  weather. 
M.  Aldrich,  of  St.  Louis,  Mo.,  to  obviate  those  objections 
and  at  the  same  time  render  the  hide  soft  and  pliant,  as 
when  first  taken  from  the  animal,  has  invented  a  chemi¬ 
cal  process  for  preparing  dry  flint  hides,  and  accomplishes 
it  in  the  following  manner : — 

First.  The  hides  are  soaked  in  clear  water  until 
limber,  then  placed  in  the  following  acid  bath — 


Acetic  acid  ........  1 

Water  .........  16 


which  will  in  from  24  to  36  hours  dissolve  the  scale  by 
combining  with  its  oxygen  or  swell  the  fibres  of  the 
hide ;  when  they  are  placed  in  the  following  bath — 

Water  .........  TO 

Carbonate  of  ammonia  ......  1 

which  have  a  strong  affinity  for  the  acid  absorbed  in 
the  first  bath,  saturates  in  from  48  to  72  hours  all  the 
acid  remaining  in  the  hide,  leaving  a  hide  in  a  naturally 
pliant  and  soft  condition,  so  perfectly  transformed  from 
a  dry  to  a  green  condition,  that  no  tanner  can  detect 
the  slightest  difference  between  stock  tanned  from  dry 
hides  so  prepared  or  from  green  hides. 

The  first  cost  of  the  acid  solutions  is  two  cents  a 
gallon,  or  $20  for  a  large  poolful,  after  which  it  can  be 
used  continually,  attended  with  no  expense  except  pump- 


310 


TANNING. 


ing  up  and  passing  it  through  the  apparatus  to  renew 
its  strength  after  it  has  been  used. 

The  second  solution  is  prepared  from  all  bate  water 
attended  by  no  expense  but  pumping. 

This  process  obviates  all  danger  of  damage  from  taint 
or  running,  for  its  action  is  so  perfectly  antiseptic  that 
hides  so  softened  may  be  kept  for  weeks  in  water  before 
being  placed  in  the  lime,  also  by  keeping  fibrous  and 
Hanky  hides  in  the  first  bath,  double  the  ordinary  time, 
they  will  pump  up  and  be  materially  improved  and  all 
without  any  breaking  whatever.  Hereafter  we  will  treat 
of  the  full  process  of  tanning  of  the  same  inventor. 


CHAPTER  LXIV. 

PROCESS  OP  TANNING  OF  H.  C.  JENNINGS. 

A  short  process  of  treating  hides,  with  the  use  of  very 
little  tan  bark,  to  make  leather  has  been  patented  by  H. 
C.  Jennings,  London.  In  the  preparation  of  thick  ox¬ 
hides  by  this  process,  the  hair  is  first  removed  in  the 
usual  manner,  either  by  steeping  them  in  a  lime  bath,  as 
in  the  old  mode,  or  by  sweating,  according  to  the  new 
methods.  If  lime  is  used,  the  hides  are  steeped  in  dilute 
muriatic  acid  after  they  are  unhaired  and  washed. 
This  opens  their  pores  and  fits  them  for  the  succeeding 
operations ;  they  are  now  piled  in  batches  of  a  dozen 
hides  in  each,  with  a  hurdle  or  wicker  between  each 
pair ;  and  they  are  then  alternately  lowered  into  tanks 
filled  with  the  following  solution. 

Tank  No.  1  is  charged  with  a  strong  solution  of  alum, 
to  which  ten  per  cent,  each  of  sulphuric  and  muriatic 
acids  are  added. 

Tank  No.  2  is  charged  with  a  concentrated  solution  of 
soda  ash,  to  which  is  added  five  per  cent,  of  tungstate 
of  soda. 

The  skins  or  hides  are  immersed  six  hours  at  a  time 
in  these  tanks,  then  withdrawn  and  drained,  and  trans¬ 
ferred  alternately  from  the  first  to  the  second,  and  vice 
versa ,  until  the  hide  is  sufficiently  hardened.  This  con- 


BERENGER  AND  STERLINGUE’S  PROCESS.  311 

dition  of  the  hide  is  known  by  cutting  a  small  piece  off 
with  a  knife.  At  this  stage  they  are  immersed  for  six 
hours  in  a  strong  solution  of  tungstate  of  soda  alone,  then 
lifted,  drained,  and  placed  in  a  liquor  of  soap  made  by 
dissolving  twenty  pounds  of  soap  in  every  ten  gallons  of 
water,  and  the  hides  agitated  in  this  until  the  strength 
of  the  soap  is  exhausted  by  being  absorbed  in  the  hides. 
Wash  them  well  in  soft  water,  and  finally  steep  them 
for  24  hours  in  a  common  liquor  of  oak  bark,  after  which 
they  are  dried  and  finished  in  the  usual  manner.  This 
process  is  too  costly. 

CHAPTER  LXV. 

BERENGER  AND  STERLINGUE’S  PROCESS. 

In  1842  Messrs.  Eerenger  and  Sterlingue  patented 
the  process  described  below.  Their  method  reduces  the 
time  occupied  in  tanning,  within  the  reasonable  limits  of 
from  four  to  five  months ;  thus  avoiding  the  extreme  of 
allowing  too  short  a  duration  for  a  process  which,  to  be 
successful,  must  be  more  or  less  gradual  or  prolonged. 

When  skins  are  deposited  in  vats  with  water  and 
layers  of  tan  the  infusion  marks  generally  25°  of  the 
hydrometer.  As  the  combination  progresses  the  strength 
diminishes,  and  after  four  months  it  generally  marks  4°. 
At  this  time  the  skins  are  transposed  in  fresh  vats,  and 
this  change  is  repeated  a  third,  and  often  a  fourth  time,  at 
every  interval  of  four  months;  each  time  the  hydrometer 
sinks  from  25°  to  about  15°,  12°,  10°.  The  introduction  of 
tannin  into  the  skin  becomes  more  and  more  slow,  owing 
to  the  obstacles  to  the  penetration  into  the  tanned  sur¬ 
faces.  The  object  of  these  manufacturers  was  to  find 
means  of  tanning  which  keep  the  skins  in  contact  with 
infusions  gradually  increasing  instead  of  diminishing. 
For  this  purpose  they  placed  in  the  vat  a  wooden  cylin¬ 
der  through  which  the  infusion  could  be  removed  by 
pumps,  and  replaced  by  fresh  and  stronger  liquor  when 
necessary.  Thus,  they  succeeded  in  tanning  in  a  com- 


312 


TANNING. 


paratively  short  time  and  avoiding  the  renewal  of  the 
contents. 

To  moisten  a  freshly  filled  pit  requires  eighty  tubs  of 
water ;  the  tan  absorbs  the  largest  portion,  leaving  about 
only  ten  tubs  of  infusion,  which  can  be  pumped  without 
injuring  the  hides  and  altering  their  relative  positions. 
Messrs.  Berenger  and  Sterlingue  avoided  this  difficulty 
by  removing  the  old  infusion  from  the  pits  at  the  same 
time  that  it  was  exactly  replaced  by  the  introduction  of 
fresh  and  stronger  liquids ;  but  their  mode  was  irregu¬ 
lar,  and  it  was  necessary  to  devise  better  means  to  attain 
their  objects. 

They  provided  a  row  of  vats  with  wooden  cylinders 
which  were  connected  above  at  a  depth  of  six  inches 
below  the  surface  of  the  pits  by  means  of  a  pipe  passing 
from  one  to  another,  which  communicated  below  by 
means  of  a  perforated  tube  with  an  open  space  under  a 
false  bottom  in  the  pit.  By  this  arrangement  it  was  only 
necessary  to  open  a  stop-cock  and  admitting  fresh  liquor 
into  the  weakest  pit  to  enable  the  fluid,  which  had  no 
other  means  of  escape,  when  this  was  filled,  to  traverse 
the  entire  range  of  pits,  filling  each  one  from  the  weakest 
to  the  strongest  in  succession  before  it  was  possible  for 
any  of  it  to  enter  the  next  one. 

Let  us  suppose  a  series  of  eight  pits  thus  arranged, 
each  provided  with  its  cylinder  opening  by  a  perforated 
tube  into  the  false  bottom,  and  connecting  with  the 
cylinder  of  the  next  pit  at  a  depth  of  six  inches  below 
the  surface.  Stratify  the  hides  with  the  tan,  in  the  end 
of  the  pit,  pour  water  into  it  in  the  ordinary  way. 
Leave  from  fifteen  to  twenty-one  days,  then  fill  a  second 
pit  with  dry  tan  and  skins,  and  since  eighty  tubs  of 
water  were  required  for  the  saturation  of  the  first  one, 
the  same  quantity  properly  graduated  is  poured  into 
the  first  pit ;  this  liquid,  on  descending,  takes  the  place 
of  that  originally  contained  into  it,  then  it  has  no  other 
means  of  escape  than  to  pass  out  in  the  second  pit  in 
quantities  exactly  proportioned  to  those  which  enter  the 
first  one.  Fifteen  or  twenty  days  after  repeat  that  ope¬ 
ration,  a  stronger  infusion  being  introduced  into  the 


BERENGER  AND  STERLINGUE’S  PROCESS. 


313 


first  pit  for  the  purpose  of  filling  the  third  one  with  the 
contents  of  the  second,  and  the  second  with  those  of  the 
first.  Continue  the  same  way  and  at  the  same  intervals 
until  the  eighth  or  last  pit  is  filled.  Close  the  commu¬ 
nicating  pipe,  pump  the  infusion  from  the  first  pit, 
take  out  the  leather  to  dry ;  deposit  in  the  pit  fresh 
hides  and  tan  ;  this  pit  now  becomes  the  eighth  pit  of 
the  series.  The  second  becomes  the  first,  and  is  sup¬ 
plied  with  eighty  tubs  of  strong  infusion. 

We  see  that  one  application  of  tan  is  alone  required  ; 
the  pits  are  not  changed  until  the  leather  is  removed, 
securing  thus  a  great  economy  of  time  and  labor.  It 
generally  lasts  from  four  to  six  months. 

An  exposure  of  six  months  in  eight  pits  is  sufficient, 
if  the  strong  infusion  is  added  every  fifteen  days ;  if  the 
operation  seems  to  progress  too  rapidly,  lengthen  the 
interval  to  three  or  four  weeks  ;  in  this  case  the  process 
requires  from  six  to  eight  months.  The  number  of  pits 
could  be  increased  or  diminished. 

The  infusion  for  watering  the  pits  is  prepared  in  the 
following  manner  : — 

As  the  leather  is  taken  out  to  dry,  the  infusion  is 
transferred  to  a  set  of  vats  which  are  provided  for  the 
purpose,  and  which  are  like  those  used  to  furnish  the 
liquor  for  a  tan  bath.  Lixiviate  these  infusions  as  we 
have  described,  and  mix  with  them  some  fresh  tan  to 
give  the  requisite  strength.  If  the  liquid  is  only  at  30° 
and  is  required  to  be  at  60°,  place  it  in  a  large  reservoir 
which  connects  with  a  trough.  This  trough,  by  means 
of  a  pipe,  communicates  with  a  second,  a  third,  and  a 
fourth  below  each  other.  All  have  pipes  running  longi¬ 
tudinally  along  their  bottoms. 

Pass  steam  along  these  tubes  so  as  to  heat  the  infu¬ 
sion  which  passes  successively  from  one  trough  to  an¬ 
other,  and  to  concentrate  it  to  any  desired  point,  so  as  to 
increase  its  strength,  and  deprive  it  of  the  fatty  matter 
and  gallic  acid  which  it  may  have  absorbed  during  its 
passage  through  the  pits.  Let  it  off  by  a  stop-cock 
into  a  reservoir  below  where  it  cools,  then  pour  it  into 
the  pits. 


314 


TANNING. 


This  system  is  applied  to  a  bath  of  tan  liquor.  How¬ 
ever,  the  skins  are  not  daily  transferred  from  the  vat 
containing  the  weaker  liquor  to  that  of  the  stronger,  as 
in  the  ordinary  method,  but  are  placed  upon  horizontal 
shelves  adapted  to  each  vat,  and  are  not  taken  out  until 
ready  for  the  tan-yard,  the  liquor  being  passed  from  vat 
to  vat  as  in  the  pits.  It  may  replace  the  old  system  of 
tanning  the  skins  by  floating  them  in  tan  and  water. 
In  that  process,  the  skins,  tan,  and  infusion  are  all  thrown 
into  the  vats ;  after  a  certain  time  the  skins  are  taken 
out,  the  infusion  is  drained  off  and  replaced  in  the  vat 
with  the  same  skins  and  fresh  barks,  the  change  being 
frequently  repeated  until  the  tanning  is  complete.  By 
this  new  method,  these  removals  are  unnecessary ;  it  is 
sufficient  to  introduce  fresh  liquors  into  the  oldest  vat 
and  keep  it  constantly  full ;  so  that  the  others  will  be 
filled  in  succession.  The  tanning  by  this  process  is 
more  complete,  regular,  rapid,  and  economical ;  it  saves 
much  labor  necessary  in  other  processes. 

The  following  is  a  description  of  the  different  appa¬ 
ratus  : — 


Fig.  15. 


Figs.  75  and  76.  Apparatus,  for  giving  the  baths  to 
hides;  1,  2,  3,  4,  5,  6,  7,  square  vats,  forming  a  series. 

Fig.  76. 


BERENGER  AND  STERLINGUE’S  PROCESS. 


315 


a.  Skins  h,  placed  from  head  to  tail,  across  horizontal 
crosspieces/*,  and  resting  upon  them  without  touching 
each  other. 

b.  Exhibits  the  bottom  of  the  pit,  with  the  false  bot¬ 
tom  taken  out ;  and  c  shows  the  latter  in  place. 

cl.  Tubes  in  the  bottoms  of  the  pits,  pierced  with  holes 
to  receive  the  infusion.  Their  vertical  parts,  e,  are  not 
pierced,  but  conduct  the  fluid  upwards  from  the  bottom 
of  one  vat  to  the  top  of  the  next  one.  Their  upper  ex¬ 
tremities  turn  horizontally  into  the  adjoining  pits,  so  that 
they  cannot  communicate  excepting  through  these 
tubes. 

g.  Horizontal  tube,  connecting  vat  No.  7  with  No.  1. 
As  all  the  vats  communicate,  fluid  poured  into  one 
readily  passes  through  all. 

i.  Cock,  to  prevent  connection  between  Nos.  1  and  7, 
when  it  is  not  desired. 

k.  False  bottom. 

l.  Arrows,  indicating  the  direction  of  the  motion  of 
infusion  from  7  to  6,  etc. 

Figs.  77  and  78.  Series  of  pits.  1,  2,  3,  4,  5,  6,  pits, 
forming  a  series. 

Fig.  77. 


a.  Skins  deposited  in  pits,  alternating  with  beds  of 
tan. 

b.  View,  or  plan  of  pits,  with  the  false  bottoms  re¬ 
moved,  and  showing  d,  tubes  curved  and  pierced  with 
holes  in  this  part  alone:  the  vertical  portion  of  the 
tube  passing  up  and  turning  over  under  the  surface,  into 
the  next  pit. 


316 


TANNING. 


c.  Plan  of  pits  with  the  false  bottom  in  place,  above 
the  tubes. 


Fig.  78. 


i.  Arrow,  showing  the  movement  of  fluid  from  one 
pit  to  another. 

k.  Bungs,  or  stoppers,  used  when  necessary,  to  pre¬ 
vent  the  passage  of  fluid. 

l.  False  bottoms,  cullendered. 

Fig.  79. 


. . — -J—&- 5- - 


Figs.  79  and  80.  Apparatus  for  regenerating  old  tan- 
liquor,  and  concentrating  it  to  the  desired  strength. 

Fig.  80. 


corniguet’s  process. 


317 


a,  b,  c,  d.  Troughs  placed  one  above  the  other,  so  that 
the  infusion  in  a  runs  down  into  b,  into  c ,  and  into  d, 
through  the  tubes  k,  k',  k",  k'",  with  the  stopcocks  o,  o', 
o",  o'". 

At  the  bottom  of  each  trough  is  a  serpentine  tube  m, 
extending  over  the  whole  surface,  as  seen  in  the  plan. 
The  vapor  enters  each  tube  upon  opening  the  stopcocks 
s,  s',  s",  s'",  in  the  tube  l. 

e.  Reservoir,  in  which  the  liquor  to  be  purified  is  first 
placed.  It  escapes  from  this  through  the  tube  g,  into 
the  first  trough.  When  this  is  full,  the  fluid  still  run¬ 
ning  from  the  reservoir,  the  cock  o  is  opened,  and  the 
warm  and  already  partly  concentrated  fluid  runs  into 
reservoir  b,  and  so  on  successively,  until  the  concentrated 
liquor  passes  through  the  cock  o""  into  a  trough  in  which 
it  is  allowed  to  cool. 

f.  Escape-pipe,  conducting  the  condensed  water  and 
waste  vapor  into  the  open  air. 

p.  Pipe,  for  the  entrance  of  steam. 

The  drawings  represent  only  six  and  seven  elements 
of  the  .series  of  pits  and  vats,  while  reference  has  been 
had  in  the  text  to  eight. 


CHAPTER  LXVI. 

CORNIGUET’S  PROCESS  OF  SUBSTITUTING  THE  FRUIT  OF 
THE  PINE  FOR  THE  BARK  IN  TANNING. 

Put  the  skins  in  the  lime,  draw  them  once  every  day, 
and  keep  them  till  they  depilate  easily. 

Wash  them  carefully.  Put  them  into  the  vats.  For 
100  calf-skins,  weighing  from  400  to  500  lbs.,  are  re¬ 
quired  200  lbs.  of  powdered  fruit,  which  is  introduced 
into  the  vat  in  five  hours  at  the  rate  of  40  lbs.  every  hour. 
Stir  them  for  six  hours,  raise  every  day,  change  them 
every  eight  days  in  summer,  and  fifteen  in  winter,  let 
them  drain  two  hours  above  the  vat. 

Put  them  back  in  half  of  the  water  used  in  the  pre¬ 
ceding  operation,  and  then  withdraw  the  first  powder, 
spread  them  one  by  one,  covering  them  with  fresh 


318 


TANNING. 


powder  so  as  to  use  300  lbs.  Leave  them  six  weeks  in 
summer  and  three  months  in  winter,  raise,  wash,  and 
drain  them  24  hours. 

Lay  them  in  dry  vats,  putting  alternately  a  layer  of 
powder,  and  a  layer  of  skin,  putting  more  powder  on 
the  thickest  parts ;  leave  three  months  and  they  are 
ready. 

The  fruit  of  the  ordinary  pine  tree,  and  the  larch  tree 
reduced  into  powder,  can  be  thus  substituted  for  oak- 
bark,  but  that  of  the  larch  tree  is  better  as  containing 
more  tannin. 


CHAPTER  L  X  V  1 1. 

VAUQUELIN’S  PROCESS. 

The  means  employed  by  Vauquelin  to  perfect  the 
process  of  tanning  rest  on  different  principles,  and  we 
have  combined  them  so  as  to  make  the  four  following 
effects  clear: — 

1st.  Not  to  alter  the  skins  by  a  chemical  reaction. 

2d.  Prepare  the  hides,  by  mechanical  means,  so  as  to 
render  them  more  apt  to  receive  the  tanning  matter. 

3d.  Shorten  the  work. 

4th.  Handling  in  tallow,  and  dressing  the  hides  by 
mechanical  means. 

The  first  operation  consists  in  preparing  the  hides  for 
tanning  by  soaking  them  while  fresh  for  a  few  hours, 
then  submitting  them  to  the  action  of  the  machine  de¬ 
scribed  hereafter.  When  the  hides  are  dried  they  are 
treated  in  the  following  manner:  Soak  them  some  time, 
about  forty-eight  hours.  Place  them  in  a  fulling  machine, 
in  which  they  are  submitted  to  the  action  of  wooden 
pestles  for  about  one  hour.  The  blows  soften  the  hides 
and  render  them  fit  to  be  cleaned. 

In  that  state  they  are  placed  in  another  apparatus, 
in  which  they  are  treated  for  some  time  by  introducing 
steam  into  the  apparatus,  so  as  to  raise  the  temperature 
to  104  or  122°.  From  there  the  hides  are  carried  in 
another  vessel  or  oven,  in  which  they  are  submitted  to 


vauquelin’s  process. 


319 


the  action  of  tepid  water  which  penetrates  and  humects 
them  for  twenty-four  hours.  The  temperature  must  be 
uniform,  for  if  the  operation  is  conducted  better  on  one 
place  than  on  another,  you  run  the  chance  of  producing 
a  hollow  skin,  and  diminish  its  quality. 

When  you  operate  on  small  quantities  at  a  time,  this 
operation  is  sufficient  to  depilate,  but  on  large  quantities 
it  is  important  to  act  quicker.  In  this  last  case  weak 
lime-water  is  used  instead  of  a  milk  of  lime,  and  the  tem¬ 
perature  is  regulated  according  to  the  number  of  skins 
operated  upon. 

When  these  operations  are  complete  the  hair  is  taken 
off  easily.  These  skins  are  then  submitted  to  the  fleshing 
with  the  help  of  machinery.  The  machine,  put  in  mo¬ 
tion  by  a  man,  acts  on  the  hides,  takes  off  all  the  fleshy 
parts  which  adhere  to  it,  and  prepares  them  for  the 
subsequent  operations.  The  advantages  of  this  prepa¬ 
ration  are,  to  submit  to  the  tanning  process  only  the 
parts  really  useful,  while  in  the  old  method  all  the  skin 
was  tanned,  and  afterwards  cut,  thus  causing  a  great 
loss.  The  parts  of  skins  thus  separated  are  used  to 
manufacture  glue. 

The  hides  thus  treated  are  put  into  the  fulling  machine, 
and  worked  with  tepid  water  for  a  certain  time  according 
to  the  nature  of  the  hide.  Then  they  are  brought  into 
the  vat,  where  they  are  impregnated  with  a  weak  solu¬ 
tion  of  tanning  liquor  for  a  few  hours,  raised  and  piled 
up,  and  two  hours  after  placed  in  a  stronger  liquor. 
The  three  first  days  raise  them  three  times  a  day,  and 
afterwards  only  once.  Submit  them  to  the  action  of  the 
fulling  machine  every  forty-eight  hours,  and  put  them 
back  for  half  an  hour  in  the  same  tanning  liquor,  where 
they  are  left  until  completely  saturated.  The  action  of 
the  pestles  of  the  machine  opens  the  skins,  and  renders 
them  more  apt  to  receive  the  tanning  substance,  and  by 
using  the  apparatus  hereafter  described,  all  the  parts  of 
the  skin  are  put  in  contact  with  the  liquor,  which  acts  on 
it  rapidly  and  uniformly.  At  last,  by  this  process  the 
operation  is  executed  much  quicker  than  by  the  old 
process. 


320 


TANNING. 


The  following  is  another  method  of  operating : — 

The  hides  being  placed  in  the  vat,  pass  through  it  a 
current  of  steam,  so  as  to  raise  the  temperature  to  about 
104°  or  116°.  The  skins  by  the  rotative  movement 
given  to  this  vat  are  projected  on  its  partitions,  then  fall 
back  on  the  bottom  from  whence  they  are  successively 
retaken.  This  operation  is  continued  for  some  time, 
till  the  hides  are  entirely  deprived  of  hair.  In  that 
state  they  are  placed  in  another  apparatus  to  which  a 
rotative  motion  is  communicated.  It  is  a  drum  to 
cleanse,  which  has  in  its  inside  a  series  of  immovable 
pins,  and  which  turn  in  a  reservoir  of  water  which  raise 
to  about  half  the  height  of  these  pins.  The  hides  in  pro¬ 
jecting  on  the  pins  are  deprived  of  their  hair  by  the 
rotative  movement  of  the  drum,  and  this  hair  falls  to 
the  bottom,  and  is  carried  away  by  the  water,  wThile  a 
metallic  grate  prevents  the  hides  going  out  from  the 
drum.  In  that  state  the  hides  can  be  cut,  and  submitted 
to  the  operation  above  described. 

The  following  gives  an  idea  of  the  manner  of  passing 
the  skins  through  the  tallow,  and  preparing  them. 

After  the  skins  are  tanned  by  the  above  or  any  other 
process,  cover  all  their  surface  with  a  fatty  matter,  com¬ 
posed  of  oil  and  tallow.  These  skins,  thus  greased,  are 
placed  in  a  cylinder,  presenting  on  its  inside  surface  a 
series  of  pins  as  we  have  explained  above.  Turn  this 
cylinder,  and  the  skins  are  projected  on  the  pins  during 
the  rotation.  This  operation  is  continued  for  half  an 
hour,  after  which  time  it  will  be  found  that  the  greasy 
matter  has  uniformly  penetrated  the  skins,  and  that 
their  surfaces  present  a  dry  aspect.  Take  them  out, 
spread,  dry,  and  prepare  them  as  usual. 

This  cylinder  is  not  absolutely  necessary,  because  this 
system  of  tanning  prepares  much  better'  the  skins  des¬ 
tined  to  receive  the  greasy  matters,  but  in  many  cases 
it  is  advantageous  to  use  them.  We  now  give  a  descrip¬ 
tion  of  the  different  apparatus  which  will  cause  this  sys¬ 
tem  to  be  better  understood. 

Description  of  the  Figures. — Fig.  81.  This  represents 
the  beating  or  fulling  machine.  A,  b.  Cog-wheels  giving 


yauquelin’s  process. 


321 


motion  to  the  shaft  o,  and  to  cams  upon  it,  which  alter¬ 
nately  raise  and  lower  the  hammers  E,  E,  E,  to  which  the 


Fig.  81. 


bar  D  serves  as  a  guide.  A  movable  trough  for  the  skins 
is  seen  below,  c,  c.  Cocks,  which  allow  the  liquid  mat¬ 
ters  contained  in  this  trough  to  escape,  h,  h.  Openings, 
through  which  the  skins  are  introduced  into  the  trough. 
I.  Rack  and  pinion,  by  means  of  which  the  trough  is 
moved  to  and  fro,  so  as  to  bring  all  parts  of  the  skins 
successively  under  the  hammer. 

Fig.  82.  Churning  vat.  This  may  consist  of  an  open 
vessel,  but  a  closed  one  will  enable  the  operator  to  main¬ 
tain  a  more  uniform  temperature.  A.  Vat,  closed  by  its 
lid.  b.  Shaft,  carrying  the  cams  or  arms  c,  c.  d,  d. 
Tubes,  through  which  cold  and  hot  water,  the  tanning 


Fig.  82. 


liquor  and  steam  are  introduced.  E.  Ladder,  by  which 
the  workman  descends  and  regulates  the  cocks,  f,  f. 
Ground  level.  G,  G.  Water  level  in  the  vat.  h.  Door, 
which  closes  the  opening  in  the  vat.  a.  Toothed  wheel, 
21 


322 


TANNING. 


communicating  its  movement  to  the  wheel,  b,  and  the 
shaft.  The  arms  of  the  shaft  are  straight,  but  may  be 
made  of  various  shapes. 

Figs.  83  and  84.  These  figures  represent  the  machine 


Fig.  83.  Fig.  84. 


for  fleshing  and  paring  the  hides  after  they  have  been 
properly  soaked  and  softened. 

It  is  composed  of  two  cylinders,  A  and  b,  of  copper,  or 
other  suitable  metal,  mounted  upon  a  framework  c,  c, 
and  forming  a  kind  of  cylindrical  press.  The  upper  one 
can  be  elevated  or  depressed  by  means  of  screws,  d,  d,  in 
the  upper  crosspiece  of  the  frame,  which  act  both  upon 
the  fixed  supports  h,  h,  and  upon  the  sides  of  the  frame. 
Upon  this  crosspiece,  a  shaft,  with  a  small  fly-wheel  i, 
works  the  endless  screws  f,  f,  which  turn  the  cog-wheels 
E,  e,  by  means  of  which  the  screws  d,  d,  are  turned  in 
either  direction.  These  screws  carry,  just  below  the 
wheel  f,  two  shoulders  or  collars,  upon  which  the  bar  K, 
is  supported,  and  at  the  extremities  of  this  bar,  two  de¬ 
scending  cushions  l  are  attached,  which  support  the 
shaft  of  the  cylinder  A,  and  which  are  elevated  or  low¬ 
ered  by  the  bar,  in  accordance  with  the  movement  of  the 
screw  d.  At  the  two  extremities  of  the  cylinders  are 
cog-wheels  of  different  diameters,  M,  n,  m',  n'.  Those 
on  the  shaft  of  the  lower  cylinder  b,  are  so  attached  to 
it,  that  it  shares  in  their  movement,  while  they  are 
movable  upon  it,  and  can  be  slid  to  the  right  or  left  by 


VAUQUELIN  S  PROCESS. 


323 


two  forks  q,  q,  fastened  to  the  p"',  which  passes  across 
the  framework.  The  wheels  m,  m',  are  geared  with  each 
other  when  the  cylinders  are  a  certain  distance  apart, 
and  those  at  n,  n',  engage  in  turn,  when  the  cylinders 
are  brought  in  contact  with  each  other,  so  that  the  cyl¬ 
inders  turn  simultaneously  in  either  of  these  positions. 
At  the  extremities  of  the  cylinders,  there  is  a  system  of 
pulleys  which  communicate  the  motion  to  the  machine 
by  means  of  straps. 

Upon  the  interior  and  posterior  faces  of  the  machine, 
two  knives,  p,  p',  are  fixed,  which  turn  upon  cushions 
supported  by  the  pieces  q,  q',  seen  on  the  frame.  The 
knife  p  has  a  cutting-blade,  which  is  retained  in  place 
and  adjusted  by  means  of  screws,  but  the  knife  p'  is  dull. 

The  skin,  placed  upon  the  upper  cylinder,  is  drawn  in, 
compressed,  and  stretched  out  in  the  direction  of  its 
length,  between  the  two  rollers.  The  wheels  m,  m',  are 
then  put  in  gear,  and  the  knife  p'  is  made  to  pass  over 
the  skin  by  pressing  it  against  the  upper  roller  by  means 
of  a  movable  piece  with  two  handles.  The  skin  being 
now  pressed  between  the  rollers  and  gradually  advancing 
through  them,  the  cutting-blade,  which  is  parallel  to 
the  surface  of  the  cylinder,  is  put  in  action,  and,  like 
the  ordinary  fleshing-knife,  it  removes  all  the  projec¬ 
tions  from  the  flesh  side,  and  equalizes  the  thickness  of 
the  skin. 

Figs.  85,  86,  and  87.  These  figures  represent  the  re¬ 


volving  cylinder  or  drum  for  depriving  the  skins  of  hair, 
which  has  already  been  partly  described. 

A.  Exterior  of  the  drum ;  b,  b,  shaft  of  cylinder ;  c, 
cylinder  d,  crossbars,  forming  the  framework;  e,  f,  sepa- 


324 


TANNING. 


rate  pieces  of  the  set  of  crossbars  ;  g,  g,  internal  surface 
of  the  cylinder;  h,  wooden  projections,  fixed  upon  this 
surface ;  i,  metallic  plate  closing  the  surface  of  the  cylin¬ 
der;  l,  door,  closing  the  aperture;  M,  m,  tubes,  through 
which  water,  tanning  liquor,  and  steam  are  introduced 
into  the  cylinder  ;  o,  ladder,  for  the  workman  who  attends 
to  the  stopcocks,  to  descend ;  p,  level  of  liquid  in  the 
cylinder ;  b,  b,  cog-wheels,  communicating  motion  to  the 
cylinder. 

Figs.  88,  89,  and  90.  These  figures  exhibit  different 


Fig.  88.  Fig.  89.  Fig.  90. 


means  of  keeping  the  skins  pressed  upon  the  table  when 
they  are  subjected  to  processes  of  paring  by  hand. 

a ,  a.  Clamp  or  press  for  maintaining  the  skin  in  place; 
b ,  b ,  the  table  ;  c,  c,  a  vertical  bar  sliding  in  a  groove  ;  d, 
the  lever  which  acts  upon  the  press ;  /,  a  catch  which 
stops  the  lever  d ;  /,  weight  at  the  end  of  the  lever;  g , 
another  lever  by  means  of  which  the  press  is  raised,  as 
has  been  before  explained. 

Fig,  91  represents  the  press  commonly  used  in  this 
mode  of  preparing  leather. 

The  committee  on  chemical  arts  of 
the  Societe  d'  Encouragement,  reported,  in 
the  Bulletin  of  the  Society,  most  favor¬ 
ably  upon  the  processes  of  Vauquelin. 
They  believe  that  the  expense  of  the 
various  methods  used  by  him  does  not 
exceed  that  of  those  ordinarily  employed, 
while  a  great  gain  is  secured  by  the 
rapidity  of  the  process,  and  the  smaller  quantity  of  tan 
required  by  it. 

This  process  being  described,  we  shall  give  the  results 
of  experiments  made  by  the  Societe  d'  Encouragement, 
and  reported  in  its  Bulletins  of  1841  and  1844. 


Fig.  91. 


vauquelin’s  process. 


325 


“African  cow-hides,  so  dried  by  the  sun  that  tanners 
thought  them  impossible  to  be  tanned,  have  been  chosen 
by  Mr.  Vauquelin  to -demonstrate  the  advantage  of  his 
process;  they  have  been  marked  and  treated  by  the 
above  process.  To  obtain  all  desired  certainty  in  the 
quality  of  the  leather,  the  committee  invited  the  best 
leather  dealers  and  manufacturers  to  assist  in  his  re¬ 
searches. 

“  After  the  skins  had  been  tanned  they  were  examined, 
and  they  were  unanimously  declared  of  good  quality,  all 
but  one,  that  one  of  the  judges  declared  incapable  of 
being  well  curried. 

“  That  skin  was  marked  and  all  were  curried,  and  all 
of  them  without  exception  were  found  perfect. 

“  The  leather  could  be  smoothed  and  greased.  By  the 
first  process  the  benefit  would  have  been  greater;  the 
second  was  more  difficult,  and  Mr.  Vauquelin  chose  it  to 
prove  that  skins  tanned  by  his  process  present  a  pecu¬ 
liar  character  for  currying — that  of  gaining  in  weight 
instead  of  losing. 

“One  of  the  skins  was  converted  into  black  leather 
wdiich  was  of  good  quality,  and  it  is  a  great  advantage 
of  this  process  to  obtain  skins  apt  to  be  used  in  different 
ways. 

“The  following  are  the  details  of  the  operation: — 


23  skins  weighing  with  hair  77  K.  (154  lbs.)  weigh  when  curried  99  K  (198  lbs.) 


1  Curried  marked  anew 
1  Dry  in  crust 
3  For  legs 
1  For  black  leather 
3  To  smooth 
1  For  strong  leather 
1  Bad  and  six  fresh 


3.500  (7  lbs.) 

3.500  (7  lbs.) 
10.  (20  lbs.) 

5.500(11  lbs.) 
14.  (28  lbs.) 

5.500(11  lbs.) 

21.500  (43  lbs.) 


6  K  (12  lbs.) 

4.500  (9  lbs.) 

U 

9.500  (19  lbs.) 
21  (42  lbs.) 


140.500  281 


“  The  work  lasted  two  months,  the  currying  had  been 
put  back  on  account  of  damp  weather,  and  the  difficulty 
of  drying. 

“The  quantity  of  tan  used  has  been  1800  lbs.,  an 
inconsiderable  proportion,  but  easily  accounted  for,  if  we 
remember  that  it  is  a  quick  process,  and  the  transforma¬ 
tion  of  the  tannin  into  gallic  acid  is  less  considerable 
than  in  the  ordinary  process.” 


326 


TANNING. 


Later,  in  1844,  a  new  report  gives  the  results  of  some 
new  experiments. 

“  100  calf-skins  weighing  360  lbs.,  three  cow-hides 
weighing  14  lbs.,  and  two  horse-hides  were  put  in  experi¬ 
ment  the  9th  of  January. 

“The  eighteenth  of  March  the  calf-skins  were  tanned, 
the  4th  of  April  the  cow-hides  were  completed,  and  the 
horse-hides  on  the  12th  of  April. 

“  One  calf-skin  was  reserved  for  another  experiment, 
the  99  others  weighed  340  lbs.,  the  three  cow-hides  18 
lbs. 

“We  see  that  calf-skins  have  been  tanned  in  68  days, 
cow  in  85,  and  horse  87,  while  by  the  usual  methods,  it 
requires  from  12  to  15  months.  Col.  Chompre,  of  the 
French  Army,  gives  the  following  notes  on  the  use  of 
M.  Vauquelin’s  leather. 

“1st.  A  piece  of  calf-skin  forming  a  patch  on  a  pair 
of  trowsers,  which  were  ridden  in  by  a  dragoon  every 
day  for  eight  months,  was  found  at  the  end  of  that  time 
in  a  perfect  state,  and  as  pliable  as  at  first. 

“  2d.  A  number  of  pairs  of  calf-skin  boot-legs  wore 
exceedingly  well,  preserving  their  firmness  and  pliability 
without  any  unusual  care  being  used  for  their  preserva¬ 
tion. 

“A  pair  of  boots  with  ordinary  tops,  and  with  soles 
made  of  the  tail  part  of  the  horse-hides,  was  worn  by  a 
non-commissioned  officer,  who  generally  wears  out  a 
number  of  shoes.  These  are  in  good  order,  and  have 
lasted,  by  his  account,  as  long  as  two  pairs  of  shoes. 

“  Five  other  pairs  of  soles  of  shoes  given  to  lancers, 
who  wear  out  a  great  many  in  service,  are  in  an  excel¬ 
lent  state  of  preservation. 

“  3d.  The  blackened  leather  used  for  belts,  girths, 
etc.,  has  also  worn  well.” 

The  conclusions  of  the  report  of  the  administrative 
council  of  the  regiment  are — that  the  leather  submitted 
to,  and  tried  by  them,  was  superior  to  any  which  had 
before  come  under  their  notice. 


OGEKEAU’S  PROCESS. 


327 


CHAPTER  LX  VII I. 

OGEREAU’S  PROCESS. 

An  eminent  Parisian  tanner,  Mr.  Ogereau,  proposes  to 
lessen  the  duration  of  the  tanning  process  by  a  methodi¬ 
cal  arrangement  of  materials.  The  skins  are  properly 
prepared  by  the  ordinary  method  of  separating  the  hair 
and  raising ;  then  he  places  alternate  layers  of  tan  and 
skins  in  a  vat  with  a  perforated  false  bottom.  This  vat 
being  full  to  the  S,  is  drenched  with  water  for  the  first 
operation,  and  with  weak  tan  liquor  for  the  succeeding 
ones.  The  liquid  penetrates  slowly  into  the  mass,  and 
having  moistened  the  contents,  runs  through  the  false 
bottom  into  a  reservoir,  from  which  it  is  carried  back 
upon  the  surface  of  the  materials. 

His  arrangement  consists  of  six  vats,#  each  one 
contains  100  domestic  or  120  imported  hides.  The 
liquid  passing  through  into  the  reservoir  is  daily  distri¬ 
buted  over  the  surface  by  pumping.  This  operation  is 
continued  for  one  month,  at  the  end  of  which  time  the 
vat  is  emptied  and  the  spent  bark  replaced  by  fresh, 
and  the  same  process  is  recommenced.  A  third  exposure 
to  fresh  tan  and  repeated  filtrations  is  necessary  to  obtain 
a  proper  tanning.  This  full  process  occupies  four 
months,  and  the  leather  it  furnishes  is  equal  in  quality 
to  that  obtained  by  the  old  method,  one  hundred  parts 
of  dry  Buenos  Ayres  hides  gives  150  parts  of  leather. 


*  Dumas’  Chimie  Appliquee. 


328 


TANNING. 


SECTION  VII. 

AMERICAN,  ENGLISH,  AND  OTHER  PROCESSES. 
CHAPTER  L  X IX. 

PROCESS  OF  TANNING  WITH  A  DECOCTION  OF  OAK 

BARK. 

The  principle  of  this  process  is  the  same  as  that  estab¬ 
lished  by  Seguin.  Oak  bark  is.  boiled  for  four  hours  in  a 
large  copper  kettle,  and  when  the  tan  is  exhausted  the 
liquor  is  conducted  by  pipes  into  vats,  where  it  is  left  to 
cool.  Soak  therein  the  hides,  press  them  often,  draw 
out  and  soak  again.  Place  them  from  time  to  time  in 
a  fresh  liquor,  if  the  first  is  too  weak  before  the  operation 
is  terminated ;  by  this  method  a  larger  quantity  of  tannin 
is  concentrated  in  a  given  space,  and  the  labor  is  less. 
If  the  leather  is  desired  whiter,  mix  with  the  liquor  a 
certain  quantity  of  powdered  bark.  By  this  process  the 
hides  are  tanned  better,  and  ten  or  twelve  days  produce 
the  same  effect  as  nine  or  ten  months  by  the  usual  me¬ 
thod.  This  is  true,  but  the  leather  thus  produced  is  not 
completely  tanned.  The  great  quantity  of  tannin  which 
is  present  rapidly  tans  the  two  surfaces,  then  they  refuse 
passage  to  the  solution,  and  the  inside  remains  in  the 
state  of  skin.  There  were  the  same  objections  to  Seguin’s 
process. 

Besides  oak  bark,  the  inventor  uses  again  oak  shavings 
and  sawdust,  and  the  ordinary  heath.  It  has  been 
ascertained  that  the  bark  of  nearly  all  trees  with  a  heavy 
wood,  contains  tannin.  They  recommend,  also,  the  use 
of  buds,  roots  and  branches  of  oak.  They  obtain  thus 
a  decoction  of  tannin  stronger  than  that  of  the  bark  of 
the  trunk  which  contains  a  thick  matter  difficult  to 
separate. 

It  had  been  shown,  as  early  as  1849,  that  the  trunk, 
roots,  middle  parts,  branches  and  leaves  of  the  oak, 
contained  tannin  in  sufficient  quantity  to  be  used  sue- 


Desmond’s  process. 


329 


cessfully  in  tanning.  These  are  reduced  into  shavings, 
or  coarse  powder,  boiled  and  used  in  the  following  man¬ 
ner  : — 

To  tan  calf-skins  or  other  light  skins,  take  200  lbs.  of 
the  middle  part  of  the  tree,  or  shavings  of  oak  branches, 
boil  them  in  a  copper  kettle,  containing  50  galls,  of  water, 
until  it  is  reduced  to  37  galls.  Draw  the  liquor,  pour  on 
the  residue  37  galls,  of  fresh  water  which  by  ebullition 
you  reduce  to  20  galls.  Keep  this  liquor  apart.  It  is 
used  to  immerse  calf-skins,  when  they  have  been  worked 
on  the  beam.  Pass  afterwards  in  the  first  solution. 

For  ordinary  hides,  take  200  lbs.  of  the  middling  part 
of  the  tree  or  branches,  150  lbs.  of  coarse  powder  of  oak, 
and  25  lbs.  of  root,  that  you  boil  in  63  galls,  of  water 
until  reduced  to  42  galls.,  draw  the  liquor,  and  on  the 
residue  pour  50  galls,  of  fresh  water  and  boil  until 
reduced  to  25  galls.  This  liquor  is  used  for  the  first 
operation  of  the  tanning.  Pass  them  afterwards  in  the 
first  decoction.  When  the  hides  have  been  submitted 
to  these  two  operations,  add  to  each  solution  some  oak 
bark,  as  much  as  necessary  to  complete  the  tanning. 
This  quantity  varies  according  to  the  strength  of  the 
decoctions. 

This  method  seems  to  us  very  incomplete,  and  the 
authors  do  not  even  indicate  the  number  of  hides  the 
above  proportion  will  tan,  nor  the  time  they  must  remain 
in  the  solution. 


CHAPTER  LXX. 

DESMOND’S  PROCESS. 

This  process,  like  the  preceding  one,  is  a  modification 
of  Seguin’s  process.  He  recommends  saturating  the 
water  with  tanning  principles  by  infusion  of  successive 
portions  of  oak  bark,  or  any  other  tanning  vegetable  ; 
and  when  the  bark  is  exhausted,  he  extracts  what  is  left 
of  gallic  acid  by  fresh  water.  To  this  last  liquor  he  adds 
y-J-Q  q  in  measure  of  sulphuric  acid,  and  leaves  the  hide 
in  till  the  hair  is  easily  removed.  When  the  swelling 


330 


TANNING. 


is  necessary,  he  leaves  the  hide  ten  or  twelve  hours  in 
water,  acidulated  with  0.05  part  in  measure  of  sulphuric 
acid,  he  washes  anew  and  fleshes  with  the  round  knife. 
He  then  leaves  the  skins  for  a  few  hours  in  a  weak  solu¬ 
tion  of  tannin,  afterwards  several  days  in  a  stronger 
solution,  which  must  be  renewed  as  the  strength  becomes 
exhausted,  till  the  skin  is  completely  tanned. 


CHAPTER  LX  XI. 

J.  BURBIDGE’S  PROCESS  WITH  EXTRACT  OF  OAK  BARK 
AND  CATECHU. 

Mr.  Borbidge  prepares  leather  with  the  extract  of  oak 
bark.  He  says  that  in  ten  days  he  obtains  this  extract 
without  any  loss  of  tannin,  which  requires  two  or  three 
months  in  the  ordinary  tanning  process.  He  regulates 
the  use  of  this  extract  with  an  hydrometer  called,  bark- 
ometer;  in  three  or  four  months  the  tanning  of  sole- 
leather  is  complete.  The  only  precaution  necessary  to 
be  taken,  is  to  begin  with  a  weak  extract  at  3°,  and  to 
increase  successively  the  strength  by  changing  the  liquor 
three  times  a  week,  so  as  to  carry  it  to  20°,  being  care¬ 
ful  to  use  the  strongest  extract  when  the  leather  is 
nearly  tanned.  His  process  increases  the  weight  of  the 
leather.  Tanners  take  one  year  to  tan  a  hide  weighing 
80  lbs.  when  green,  and  it  weighs  only  40  lbs.  when 
tanned.  In  three  months  Mr.  Burbidge  tans  a  similar 
hide  which  shows  a  weight  of  48  lbs.,  which  demon¬ 
strates  that  the  excess  of  time  employed  is  injurious  to 
the  leather.  He  does  not  use  more  oak  bark  than  they 
do,  that  is  to  say,  about  four  to  five  lbs.  for  every  pound 
of  leather. 

England  using  yearly  117,000  tons  of  oak  bark,  of 
which  1 00,000  are  imported  from  Holland,  Mr.  Burbidge 
wishing  to  liberate  his  country  from  this  kind  of  tribute, 
proposes  to  substitute  for  oak  bark  the  terra  japonica, 
which,  according  to  Mr.  J.  Dauks,  has  ten  times  greater 
•tanning  properties  than  oak  bark.  According  to  the 
experiments  of  Sir  H.  Davy,  the  specific  gravity  of  cate- 


kleman’s  process. 


331 


chu  and  oak  bark  are  : :  8| :  1.  Then  catechu  worth  in 
England  £33  the  ton,  then  it  is  equivalent  to  82  tons 
oak  bark,  which  at  £10  the  ton  makes  £85.  It  is  clear 
that  there  is  a  large  saving.  The  previsions  of  Mr.  Bur- 
bidge  have  been  realized,  for  catechu  is  now  extensively 
used. 


CHAPTER  L  X  X  1 1. 

KLEMAN’S  PROCESS. 

Oak  bark,  such  as  is  used  in  tanning  skins,  is  usually 
taken  off  while  the  tree  is  in  sap.  It  is  dried  in  order 
to  preserve  it,  and  it  is  introduced  into  the  tanning  pit 
at  the  same  time  as  the  skins,  together  with  the  requisite 
quantity  of  water.  But  it  will  be  understood  that  the 
tanning  property  as  well  as  the  chemical  composition  of 
the  bark  must  vary,  according  as  the  drying  is  quick  or 
slow,  and  the  greater  or  lesser  period  of  time  during 
which  the  bark  is  allowed  to  be  exposed  to  dampness 
before  the  tanning  begins.  In  most  cases  the  bark  un¬ 
dergoes  a  commencement  of  acetous  fermentation,  which 
is  completed  in  the  tanning  vats. 

Mr.  Kleman  recommends  the  following  mode  of  ope¬ 
ration,  in  order  to  utilize  to  the  best  advantage  the 
tanning  principle  existing,  whether  in  gall-nuts  or  in 
oak  bark. 

The  bark,  while  still  fresh,  should  be  reduced  to  small 
pieces  and  placed  in  a  cask.  Add  sufficient  water  to 
cover  the  stuff,  and  close  the  cask  hermetically,  so  as  to 
prevent  the  action  of  the  oxygen  of  the  atmosphere. 
Leave  the  mixture  undisturbed  during  a  few  weeks,  in 
order  that  the  principles  soluble  in  water  may  become 
thoroughly  dissolved,  and  dissolve  the  liquid  to  separate 
it  from  the  bark.  If  this  liquid  is  subjected  to  a  gentle 
heat  of  113  to  115°,  it  will  enter  into  vinous  fermenta¬ 
tion,  and  will  then  contain  enough  alcohol  to  mark  1  to 
2°.  If  a  skin  is  placed  in  this  solution,  it  will  become 
very  rapidly  tanned,  but  it  will  be  hard  and  horny,  be¬ 
cause  the  liquor  is  too  much  concentrated.  If  on  the 


332 


TANNING. 


contrary  it  be  diluted  with  water,  one  part  liquor  and 
four  parts  water,  excellent  results  will  be  obtained; 
skins  thus  tanned  are  more  supple  and  the  grain  is 
closer  than  when  they  are  tanned  by  the  ordinary 
method.  Moreover,  by  this  new  method,  the  same 
quantity  of  bark  will  produce  more  tanning  matter. 
It  is  not  advisable  to  boil  bark  in  water,  because  boiling 
coagulates  the  albuminous  matter  which  induces  fer¬ 
mentation.  The  author  has  assured  himself  by  experi¬ 
ments  of  his  own,  that  bark  which  has  only  undergone 
vinous  fermentation  gives  much  better  results  than  that 
which  has  been  subjected  to  acetous  fermentation. 

CHAPTER  LXXIII. 

SPILSBURY’S  PROCESS  BY  PRESSURE. 

The  hides  are  very  carefully  depilated  and  prepared. 
They  have  all  the  holes  sewed  up,  so  as  to  render  them 
water-tight;  they  are  then  stretched  by  means  of  clamps 
upon  rectangular  wooden  frames.  The  frame  is  exactly 
overlaid  by  another  similar  frame,  which  is  screwed 
down  to  confine  the  edges  and  make  them  water-tight. 

Another  hide  is  stretched  as  before  over  the  upper 
ledges  of  this  second  frame,  and  a  third  frame  screwed 
upon  it  as  above.  The  whole  three  are  bolted  together 
by  means  of  clamps,  so  as  to  form  a  water-tight  vat. 
The  frames  are  then  set  upright,  and  the  ooze  allowed 
to  flow  into  the  space  intervening  between  the  two 
others  through  a  pipe  leading  into  it  from  a  reservoir 
above.  A  hydrostatic  pressure  is  thus  maintained,  and 
the  liquid  column  forces  the  ooze  through  the  hide  by 
slow  infiltration,  and  brings  thus  all  parts  in  contact 
with  the  tannin. 

In  the  bottom  of  the  vat  is  a  stop-cock  to  allow  the 
escape  of  the  air  as  the  ooze  enters,  and  the  exit  of  the 
spent  liquor  when  the  operation  is  done  ;  but  it  must  be 
closed  carefully  when  the  vats  are  full  of  liquor  and  in 
operation.  There  is  also  a  stop-cock  in  the  pipe  leading 


spilsbury’s  process. 


333 


from  the  reservoir  to  the  vat,  to  shut  off  communication 
when  the  operation  is  completed. 

Let  off  the  exhausted  liquor  by  the  stop-cock,  replace 
it  by  fresh,  and  when  the  skins  are  completely  tanned 
take  the  frames  apart,  pare  off  the  edges,  and  dress  the 
leather  as  usual. 

This  process  is  rapid,  but  the  time  varies  according 
to  the  pressure,  the  strength  of  the  solution,  and  the 
quantity  of  the  skins.  There  is  more  or  less  loss  on 
account  of  the  clippings  and  sewing  of  the  skins.  This 
method  has  not  been  as  successful  as  it  was  originally 
anticipated. 

Messrs.  Drake  and  Chaplin  have  modified  this  pro¬ 
cess.  Mr.  Drake  gives  to  the  hides  prepared  as  usual 
an  incipient  tanning  by  immersion  in  weak  ooze.  After 
the  necessary  handling,  he  takes  them  out  and  sews 
them  together  at  the  edges,  grain  side  within,  in  pairs, 
so  as  to  form  water-tight  bags,  with  small  holes  at  the 
end  for  the  admission  of  the  tan  liquor.  By  means  of 
loops,  he  suspends  the  bags  between  two  upright  wooden 
racks,  to  prevent  bulging  when  full.  The  cold  ooze  is 
introduced  by  a  funnel,  and  by  keeping  the  bag  dis¬ 
tended,  creates  a  pressure,  which  causes  the  liquid  to 
infiltrate  through  the  skin. 

The  fluid  passing  through  is  received  in  a  vessel  be¬ 
neath,  and  returned  to  the  sack.  When  the  skin  becomes 
firm  and  hard  towards  the  close  of  the  operation,  the 
temperature  of  the  room  is  raised  from  68  to  149°,  and 
is  maintained  till  the  skins  begin  to  darken  in  places, 
and  the  liquid  ceases  to  lose  strength.  Take  them 
down,  empty  them  of  their  contents,  and  prepare  as 
usual. 

The  elevation  of  temperature  promotes  the  infiltra¬ 
tion  of  the  ooze.  To  prevent  indentations,  the  position 
of  the  bags  should  be  occasionally  shifted. 

By  this  process  a  skin  can  be  tanned  in  ten  days ;  the 
appearance  is  very  favorable ;  but  we  can  say  nothing 
about  the  quality  and  durability. 

Mr.  Chaplin  lays  the  bags  in  an  inclined  position, 
and  turns  them  frequently  so  as  to  equalize  the  tanning. 


334 


TANNING. 


One  great  objection  to  this  process  is,  that  the  hides 
are  not  equally  permeable — some  portions  imbibing  the 
liquor  more  readily  than  others.  The  leather  is  weak¬ 
ened  by  the  prolonged  distension  of  the  hides. 


CHAPTEE  LX  XIV. 

M.  W.  DRAKE’S  PROCESS. 

M.  W.  Drake  has  modified  Spilsbury’s  process.  After 
the  hides  have  received  the  usual  preliminary  operations 
in  a  weak  liquor  of  tan,  they  receive  a  first  tanning 
before  being  submitted  to  the  cold  infiltration.  Then 
he  places  skins,  as  much  as  possible  of  the  same  size, 
and  same  form,  and  sews  them  with  waxed  thread  so  as 
to  form  a  bag,  solid  enough  to  retain  the  solution  of  tan. 
Then  he  suspends  these  bags  with  the  help  of  ropes, 
sewed  to  their  sides  with  tapes.  At  the  upper  end  of 
the  bag  is  an  aperture  large  enough  to  introduce  a  fun¬ 
nel,  by  the  means  of  which  the  cold  liquor  is  introduced 
until  the  bag  is  full.  After  a  certain  time,  variable 
according  to  the  quality  of  the  skins,  their  exterior  sur¬ 
face  becomes  moist,  and  drops  begin  to  form  below  the 
bag.  This  liquid  is  received  in  a  convenient  vessel,  and 
when  a  sufficient  quantity  is  collected,  it  is  poured  anew 
into  the  bag.  When  the  hides  become  hard  and  firm, 
while  all  the  parts  are  equally  moist,  raise  the  tempera¬ 
ture  from  68  to  149°;  maintain  this  temperature  until 
all  the  skins  have  become  hard  and  firm  at  all  the 
points.  When  the  skins  begin  to  blacken  in  some  parts, 
and  the  liquor  does  not  diminish  in  strength,  the  skins 
are  tanned.  Then  empty  the  bag  by  cutting  the  sew¬ 
ing,  and  terminate  the  operation  in  the  usual  manner. 
By  this  process  a  skin  can  be  tanned  in  ten  days,  while 
by  the  ordinary  method  it  requires  ten  months. 


botch’s  quick  process. 


335 


CHAPTER  LXXY. 

BOTCH’S  QUICK  PROCESS  OF  TANNING  LEATHER. 

This  process  consists  in  causing  tannin  to  penetrate 
the  skins  by  moistening  them  with  tan  liquor  upon  one 
side,  while  the  water  which  passes  through  the  pores  is 
made  to  evaporate  upon  the  other  by  artificial  heat. 
Thus  the  greater  part  of  the  tannin  remains  in  the 
leather,  and  the  strength  of  the  liquid  increases  instead 
of  diminishing.  By  this  method  leather  can  be  tanned 
in  ten  days. 

The  skins  are  limed  in  the  usual  manner,  soaked, 
and  handled  in  a  weak  tan  liquor  for  raising  and  color¬ 
ing  them.  They  are  prepared  and  cleaned,  carefully 
examined,  and  if  any  holes  are  found  they  are  pieced 
and  sewed. 

They  work  two  skins  at  a  time,  and  they  stitch  to- 


Fig.  92. 


gether  at  the  edges  those  of  equal  size  with  tarred 
thread;  they  suspend  them  by  cords  (Pig.  92)  to  the 


336 


TANNING. 


pegs  s,  s ,  s,  s ,  which  project  from  the  bar  (a).  This 
bar  is  the  top  of  a  wooden  rack  a,  b,  c ,  and  there  is  a 
similar  rack  on  the  other  side  of  the  bag  of  skins,  so 
that  the  latter  can  be  compressed  in  such  a  manner  as 
to  make  it  retain  its  shape  when  full  of  fluid ;  between 
the  two  ranges  of  uprights,  which  are  made  to  approach 
one  another  by  screws  e,  e,  an  opening  about  an  inch  in 
length  is  left  on  the  upper  part  of  the  bag  for  the  re¬ 
ception  of  the  funnel,  through  which  the  tan  liquor  is 
poured  in.  The  funnel  may  be  conveniently  placed  in 
the  neck  or  collar,  seen  in  the  figure  alongside  of  the 
rack. 

The  figure  93  represents  a  section  of  the  side  view 
of  the  rack,  and  s,  s,  the  pegs  upon  the  head  of  the 
rack,  from  which  the  bag  of  skins  is  suspended.  The 
inner  sides  of  the  central  bars  comprising  the  rack  are 
hollowed  out  in  the  form  of  arcs  of  a  large  circle,  as  seen 
below.  The  skins  being  thus  suspended,  pour  the  cold 
tan  liquor  into  the  bag  until  full.  After  a  certain  time, 
varying  according  to  the  thickness  of  the  hide,  the  out- 


Fig.  93. 


h 


ZA. 


Fig.  94. 


side  becomes  moist,  and  the  water  which  filters  through 
drops  into  the  gutter  h ,  and  flows  into  a  receptacle 
placed  below  its  spout.  This  liquid,  as  soon  as  cold,  is 


KNOWLIS’S  PROCESS. 


337 


poured  back  into  the  bag  to  keep  it  full,  and  the  supply 
of  the  fluid  is  kept  constantly  in  proportion  as  it  loses 
by  evaporation. 

When  the  surface  of  the  skin  becomes  firm  to  the 
touch,  and  equally  moist,  the  air  of  the  room  is  gradually 
heated  from  70  to  150°,  and  kept  thus  until  the  skins 
become  firm  and  hard  in  every  part,  and  assume  a  brown 
color,  and  until  the  strength  of  the  liquid  in  the  bags 
remains  the  same.  The  skins  are  then  thoroughly  tanned. 

Take  them  from  the  frame,  empty  them,  dry  and 
prepare  them  as  usual. 

The  position  of  the  skins,  during  the  process,  Fig.  95. 
must  be  changed  often,  so  that  the  bars  of  the 
frame  may  not  press  for  too  long  a  time  upon 
the  same  parts. 

The  time  of  tanning  varies  according  to  the 
thickness  of  the  skin,  their  change  of  position, 
the  strength  of  the  liquor,  the  regulation  of 
heat,  etc. 

The  annexed  figure  shows  a  section  of  the 
rack ;  b ,  b ,  lower  part  of  the  rack ;  c,  c,  bars 
of  the  two  racks  placed  so  as  not  to  be  opposite 
to  each  other. 


CHAPTER  LXXVI. 

J.  F.  KNOWLIS’S  PROCESS. 

Knowlis’s  process  is  an  improvement  of  the  above. 
He  suspends  the  hides  in  an  air-tight  vessel,  of  a  capacity 
larger  than  their  dimensions.  He  hangs  the  hides  at 
regular  intervals,  and  keeps  them  distended  by  means 
of  weights  attached  to  their  lower  ends.  In  the  upper 
portion  of  the  vat  is  an  opening,  with  a  movable  cover 
for  the  entrance  of  the  workman.  In  the  side,  and  near 
the  top,  is  a  tube  with  a  stopcock,  and  coupling  screw 
for  connecting  with  an  air-pump,  and  in  a  corresponding 
position  on  the  opposite  side,  is  a  similar  tube  for  the 
admission  of  air  to  create  external  pressure  as  may  be 
required.  As  soon  as  a  vacuum  is  obtained,  the  con- 
22 


338 


TANNING. 


tents  of  the  vat  are  left  in  repose  for  24  hours,  after 
which  the  tanning  liquor  is  drawn  off,  and  the  appara¬ 
tus  allowed  to  remain  empty  for  two  or  three  hours  to 
permit  the  entrance  of  the  air.  Repeat  this  operation 
several  times  till  the  hides  are  perfectly  tanned. 

The  ooze  is  renewed  after  each  exhaustion  of  the 
vessel,  and  the  first  liquid  should  be  weak,  and  as  the 
operation  proceeds,  the  strength  is  increased. 

This  process  really  accelerates  the  absorption  of  tan¬ 
nin  by  the  hides,  and  saves  time  and  labor.  But  to  all 
these  processes  we  prefer  the  one  described  in  the  follow¬ 
ing  chapter. 


CHAPTER  LXXVII. 

TANNING  APPARATUS  OF  D.  ALDRICH,  OF  ST.  LOUIS,  MO. 

Mr.  Dennis  Aldrich,  of  St.  Louis,  Mo.,  patented,  in 
1860,  the  following  apparatus,  of  which  we  shall  give  a 
full  description,  as  we  look  upon  it  as  a  decided  im¬ 
provement. 

Fig.  96  is  the  plan  of  a  tan-yard,  with  its  apparatus 
constructed  and  arranged  according  to  his  invention,  the 
vats  and  tanks  having  their  covers  removed  to  show  the 
apparatus  inside  of  them. 

Fig.  97  is  a  vertical  section  of  the  apparatus  in  the 
plane  indicated  in  Fig.  96. 

Fig.  98,  vertical  section  of  the  same  in  the  plane  indi¬ 
cated  in  Fig.  96. 

Fig.  99,  vertical  section  of  one  of  the  tan  vats  in  the 
plane  indicated  in  Fig.  96. 

Similar  letters  of  reference  indicate  corresponding 
parts  in  the  several  figures. 

H  H\  Tan  vats. 

I.  Handler. 

J.  Tan  leech. 

K.  Bat  vat. 

L  U.  Tan  liquor  vats. 

M.  Bate  leech. 

N.  Bate  tank. 


TANNING  APPARATUS  OF  D.  ALDRICH. 


339 


Fig.  96. 


Fig.  91. 


O.  Lime  tank. 

P.  Lime  leech. 

R.  Pool. 

8.  Lime  vat. 

These  tanks  and  vats  are  arranged  in  three  rows,  as 


340 


TANNING. 


Fipr.  98. 


shown  in  Fig.  96,  for  the  convenience  of  making  the 
several  pipe  connections.  The  said  tanks  and  vats  are 
all  made  of  wood,  calked  and  pitched  inside  to  make 
them  tight,  of  the  usual  or  of  any  convenient  horizontal 
area,  and  about  6  feet  deep,  and  every  one  is  pro¬ 
vided  with  a  movable  lid,  a ,  fitted  in  a  deep  rebate 
formed  recess  provided  round  the  top  of  the  tank,  such 
recess  being  deep  enough  to  allow  the  lid  to  be  covered 
with  water,  and  to  enable  its  edges  to  be  covered  with 
suitable  paste  or  cement,  to  prevent  the  entrance  of  air, 
when  a  partial  vacuum  is  produced  in  the  tank  or  vat 
as  hereafter  described :  A  A  are  two  pipes,  which  he 
calls  liquor  pipes,  arranged  one  above  the  other  be¬ 
tween  the  middle  and  one  of  the  outer  rows  of  tanks 
and  vats,  and  each  one  connecting  with  tan  vats,  H  H', 
and  with  tan  liquor  tanks,  L  L\  with  the  handler,  I, 
and  tan  leech,  J,  by  means  of  a  number  of  small  branch 


TANNING  APPARATUS  OF  D.  ALDRICH. 


341 


pipes,  5,  5,  each  fitted  with  a  stopcock,  1,  by  which  either 
of  the  said  tanks  or  vats  may  be  shut  from  the  liquor 
pipes. 

The  said  branch-pipes,  5,  5,  do  not  terminate  in  the 
walls  of  the  tanks  or  vats,  but  enter  upright  pipes,  6,  6, 
which  are  arranged  close  to  the  interior  of  the  said  wall 
within  the  said  tanks  or  vats,  such  pipes,  6,  6,  being 
closed  at  their  upper  ends,  but  open  at  their  lower  ends, 
which  are  within  about  one  inch  of  the  bottom  of  the 
tanks  or  vats,  and  being  furnished,  just  below  where  the 
branches  5,  5  connect  with  them,  with  three  way-cocks 
2,  2',  by  which  the  said  pipes  are  made  to  communicate 
either  with  the  bottom  or  the  upper  part  of  their  respec¬ 
tive  vessels,  b  b'  are  two  pipes,  which  he  calls  conduct 
pipes,  arranged  one  above  the  other  between  the  middle 
and  the  other  outer  row  of  tanks  and  vats,  and  each  one 
connecting  the  pool  R,  lime  vat  S,  lime  leech  P,  lime 
tank  O,  and  bate  vat  K ,  bate  leech  M,  and  bate  tank  N, 
by  means  of  short  branch-pipes  5,  5,  which,  like  the 
branch-pipes  of  the  liquor  pipes  A  A ,  are  furnished  with 
stopcocks  1,  l,and  like  these  pipes  terminate  in  upright 
pipes  6,  6,  which  are  arranged  within  the  tanks  and  vats, 
and  provided  with  three  way-cocks  2,  2,  in  all  respects 
like  the  pipes  6,  6,  first  described.  These  pipes  and 
cocks  are  all  best  shown  in  Fig.  98. 

E  E'  are  two  air-pipes  arranged  one  between  the  mid¬ 
dle  and  each  of  the  other  rows  of  tanks  and  vats,  above 
the  liquor-pipe,  and  conduct  pipes  with  branches  9  9 
connecting  the  two  tan  liquor  tanks  L  L',  the  bate  tank 
N,  and  lime-tank‘0  with  the  air. tank  X.  These  bran¬ 
ches  9  9  communicate  with  the  tanks  and  vats  near  the 
tops  thereof,  and  each  of  those  connecting  the  air-pipe 
with  the  air-tank,  is  furnished  with  a  stopcock  8,  and 
each  of  the  others  with  a  stopcock  7. 

The  air-tank  X,  which  must  be  a  perfectly  air-tight 
vessel,  has  connected  with  it  an  air-pump  W,  by  which 
to  extract  it,  said  pump  being  worked  by  hand  or  by 
steam. 

Each  of  the  tan  vats  H  H'  is  connected  with  the  ad¬ 
jacent  tan  liquor  tank  L  or  L'  by  means  of  a  short  pipe 


342 


TANNING. 


9  filled  with  a  stopcock  h.  These  pipes  do  not  open 
directly  into  the  vat  or  tank,  but  connect  with  the  ver¬ 
tical  pipe  6  having  closed  the  upper  ends,  but  opened 
the  bottoms,  arranged  close  against  the  sides  of  the  vat, 
and  tank,  like  the  pipes  6,  with  which  the  branches  5 
of  the  liquor  pipe  and  conduct  pipe  connect. 

These  pipes  6  are  fitted  with  three  way  cocks  2  like 
those  2  connected  with  the  branches  5.  The  bate  leech 
M  is  connected  with  the  bate  vat  K  and  bate  tank  iVby 
similar  pipes  9  and  6,  and  said  pipes  are  furnished  with 
similar  stopcocks  h  and  three  way  cocks  2,  the  said  pipe 
6  running  through  the  false  bottom  of  the  lime  leech. 
The  tan  liquor  tanks  are  each  furnished  with  an  air  cock 
3  in  its  cover  for  the  admission  of  air,  when  necessary. 
The  stopcocks  1  1  and  h  h  are  each  surrounded  by  a  box¬ 
ing  4,  which  serves  to  collect  any  leakage,  and  by  keep¬ 
ing  these  boxes  filled  with  water,  the  cocks  are  rendered 
air-tight. 

The  leeches  J,  M,  and  P,  are  each  constructed  with  a 
false  bottom  13,  which  is  about  two  inches  above  the 
main  bottom.  The  central  portion  of  these  false  bottoms 
is  perforated ;  but  towards  the  sides  of  the  leeches  the 
said  bottoms  have  an  upward  inclination,  and  the  in¬ 
clined  portions  are  not  perforated. 

The  pool  P,  lime  vat  S,  vats  K,  and  handler  J,  each 
contain  a  cylindrical  reel  F,  whose  ends  are  composed  of 
narrow,  radial  slats,  and  rings  of  wood,  and  whose  sides 
are  composed  of  narrow  longitudinal  slats  and  hoops  of 
the  same  material.  These  cylinders  have  central  shafts 
fitted  to  work  in  bearings  in  the  ends  of  the  vessels  in 
which  they  are  placed,  and  each  is  divided  into  four 
compartments  by  slatted  partitions,  as  exhibited  in  Fig. 
97,  in  the  handle  I;  and  each  of  these  compartments  is 
furnished  with  a  hinged  door,  of  the  whole  length  of  the 
cylinder,  for  the  introduction  of  the  hides. 

To  provide  for  the  rotary  motion  of  the  cylinder  Ft 
each  of  the  vessels  containing  the  said  cylinders  con¬ 
tains  also  a  pulley  12,  which  is  secured  to  a  short  shaft 
working  in  bearings  in  brackets  secured  to  one  side  of 
the  vessel ;  a  band  K  is  applied  to  run  round  the  out- 


TANNING  APPARATUS  OF  D.  ALDRICH. 


343 


side  of  the  reel.  The  shaft  of  the  pulley  12  is  provided 
at  one  end  with  a  crank  6,  which  is  connected  by  a  short 
vibrating  connecting  rod  6,  with  a  vertical  piston  rod  c, 
whose  piston  works  air-tight  in  an  upright  cylinder  14, 
attached  to  the  lid  of  the  vessel,  said  rod  passing  through 
the  top  of  said  cylinder,  for  the  purpose  of  enabling  it 
to  be  worked  up  and  down  by  hand,  or  by  suitable  mo¬ 
tive  power  applied  outside  of  the  vessel  to  promote  a 
rotary  motion  of  the  pulley  12,  and  reel. 

Each  of  the  tan  vats  H,  H\  contains  a  horizontal 
frame  6r,  of  wood,  having  slats  extended  from  side  to 
side,  to  hang  the  hides  upon.  Each  of  these  frames  is 
balanced  upon  the  ends  of  the  rockers  e,  e ,  attached  to 
a  rack  shaft  d,  which  extends  across  the  vat,  and  works 
in  bearings  in  the  sides  thereof.  The  said  shaft  is  fur¬ 
nished  with  an  arm  /,  which  is  connected  by  a  link  m, 
bell  crank  lever  n,  and  vibrating  connecting  rod  p,  as 
shown  best  in  Fig.  99,  with  a  vertical  piston  rod  C,  which 
works  through  a  cylinder  14,  attached  to  the  lid  a,  of 
the  vat,  in  the  same  manner  as  the  piston  rods  by  which 
the  reels  are  operated.  By  working  this  rod  c,  c,  up  and 
down,  a  reciprocating  motion  in  a  nearly  horizontal  di¬ 
rection  is  imparted  to  the  frame  G. 

The  process  of  tanning  with  this  apparatus  is  con¬ 
ducted  in  the  following  manner:  A  number  of  hides  are 
placed  in  each  of  the  compartments  of  the  reel  JF,  in  the 
pool  R,  in  which  there  must  be  sufficient  clear  water  to 
keep  the  reel  submerged;  and  the  same  reel  is  then  set 
in  motion  by  power  applied  to  its  piston  rod  C,  and  kept 
rotating  for  about  six  hours,  or  until  the  hides  are  per¬ 
fectly  cleansed  of  dirt,  blood,  or  saline  matter  that  may 
have  been  in  them — the  water  being  changed  as  often 
as  it  becomes  dirty,  during  this  part  of  the  process,  by 
allowing  it  to  run  off  and  introducing  fresh  water  by 
pipes  and  cocks  not  necessary  to  be  described  here. 

From  the  reel  JF,  of  the  pool,  the  hides  are  removed 
to  the  reel  F  in  the  lime  vat  A,  which  then  has  its  lid 
put  on  and  secured  closely ;  the  lime  leech  having  been 
charged  with  slacklime  water,  is  introduced  above  the 
charge  by  suitable  means  not  necessary  to  be  described, 


344 


TANNING. 


and  the  lime  vat  8  is  placed  in  communication  with  the 
lime  leech  P,  and  with  the  lime  tank  O,  by  means  of  the 
conduit-pipes  P,  B,  and  its  branches  5,  by  opening  the 
stopcocks  1,1,  and  the  lime  tank  O  is  placed  in  com¬ 
munication  with  the  air  tank  X,  by  opening  the  proper 
stopcocks  7  and  8,  in  the  branches  of  the  air  pipe  E. 
Vent  is  then  given  to  the  lime  leech  P  by  removing  its 
lid,  leaving  it  loose ;  and  the  air  tank  X,  lime  tank  O, 
and  lime  vat  S  are  exhausted  by  setting  the  air  pump 
W  in  operation ;  and  the  lime  vat  S  is  filled  with  lime 
water  forced  from  beneath  the  bottom  of  the  lime  leech 
P,  by  atmospheric  pressure ;  said  water  passing  up  the 
pipe  6,  of  the  lime  leech,  through  the  branches  5,  and 
pipes  P,  into  the  lime  vat  S.  When  it  is  desired  to 
strengthen  the  lime-water  in  the  vat  8,  the  lime  leech 
is  put  in  connection,  as  befoi*b  described,  with  the  vat  S, 
and  put  in  direct  communication  with  the  lime  tank  O, 
by  opening  the  stopcocks  h,  between  them,  after  which, 
by  giving  vent  to  lime  vat  8,  by  opening  its  lid,  the  lid 
of  the  leech  P being  in  the  same  time  closed,  and  placing 
the  lime  tank  into  communication  with  the  air  tank  and 
starting  the  air-pump,  the  water  is  forced  back  into  the 
lime  leech  P.  For  this  operation  the  three  way-cocks 
2,  of  the  pipes  6,  in  the  lime  leech  should  be  turned  to 
admit  the  water  above  the  lime  that  it  may  percolate 
through  it.  The  lime  being  thus  strengthened  may  be 
forced  back  in  the  lime  vat  8,  as  before  described.  By 
the  use  of  two  lime  tanks,  O,  a  constant  circulation  of 
liquor  can  be  kept  up  through  the  lime  leech  P,  and 
lime  vat  8;  while  the  hides  are  in  the  lime  vat  8,  the 
cylinder  may  be  kept  in  motion  constantly  or  set  in 
motion  from  time  to  time. 

When  the  hides  have  been  sufficiently  limed  they  are 
removed  from  the  lime  vat  8t  and  prepared  for  the  bate, 
and  put  in  the  reel  F,  of  the  bate  vat  K ,  whose  connec¬ 
tion  with  the  bate  leech  if,  and  bate  tank  if,  and  air 
tank  is  similar  to  the  connection  of  the  lime  vat  with 
its  respective  leech  and  tank,  and  with  the  air  tank,  and 
the  operation  of  the  bate  vat  is  conducted  in  the  same 
manner  as  that  of  the  lime  vat,  the  bate  leech  having 


TANNING  APPARATUS  OF  D.  ALDRICH. 


345 


been  previously  charged  with  bating  material.  Having 
been  thus  prepared  for  coloring  the  hides  are  placed  in 
the  reel  F,  of  the  handler  I,  which  by  opening  and 
closing  the  proper  cocks  in  the  liquor  pipes,  A,  A',  and 
air  pipe  E,  can  be  put  in  communication  with  the  tan 
liquor  tanks  L  L',  and  tan  leech  /,  and  the  hides  be 
operated  upon  in  the  same  manner  as  in  the  lime  vat 
and  bate  vat,  except  that  tan  liquor  is  used  in  place  of 
the  lime  or  leech  liquors. 

After  having  been  sufficiently  colored  the  hides  are 
suspended  from  the  slats  of  the  frames  G  G,  in  the  tan 
vats  H  H',  and  after  the  covers  of  said  vats  have  been 
put  on  and  secured,  the  tan  vat  H  is  connected  with  the 
tan  leech  J  by  one  of  the  pipes  A  A,  and  its  branches 
5  5,  by  opening  the  proper  cocks  1,1,  and  is  connected 
with  its  adjacent  liquor  tank  L  by  opening  the  cock  h 
of  their  respective  direct  connection  pipe  9,  and  the 
said  two  liquor  tanks  L  are,  by  means  of  the  air  pipe 
E,  and  its  branches  9,  brought  into  communication  with 
the  air  tank  X,  and  the  other  liquor  tank  L'  is  by  means 
of  the  other  of  the  pipes  A'  A',  and  its  branches  5  5, 
brought  into  communication  with  the  tan  leech  J.  The 
pipe  6,  of  the  tan  leech,  which  is  in  connection  with  the 
tank  L ',  having  its  cock  turned  to  such  position  as  to 
open  the  upper  aperture  of  the  said  pipe,  and  the  other 
pipe,  6,  of  the  said  leech  having  its  cock  reversed.  Then 
by  opening  the  cock  3,  of  the  tank  L',  and  setting  the 
air  pump  in  operation  to  exhaust  the  air  tank  X,  the 
liquor  is  forced  by  atmospheric  pressure  from  the  said 
tank  L  to  the  tank  leech,  where  it  falls  upon  and  perco¬ 
lates  through  the  tanning  material  and  passes  through 
the  false  bottom  13,  from  below,  which  is  caused  to  pass 
by  the  opposite  pipe  6  of  the  leech  to  that  from  which 
it  enters,  and  the  liquor  pipe  A  or  A',  to  the  tan  vat  H. 
By  opening  and  closing  the  cocks  to  place  the  tan  vat 
H'  in  the  same  relation  to  its  respective  tank,  and  Z/,  as 
just  described,  of  H  and  L,  and  reversing  the  above  de¬ 
scribed  relation  of  the  tanks,  L ,  E\  with  the  tan  leech 
and  air  tank,  opening  the  air  cock  of  L  and  setting  the 
air  pump  in  operation,  the  vat  H  may  be  filled  from  the 


346 


TANNING. 


tank  L ,  by  completely  reversing  the  communication  be¬ 
tween  the  tan  liquor  tank,  air  tank,  and  tan  leech  from 
either  of  the  above  described  conditions,  the  liquor  may 
be  returned  through  the  tan  leech ;  and  by  a  proper 
manipulation  of  the  cocks,  while  the  air  pump  is  in 
operation,  a  constant  current  of  tan  liquor  through  the 
tan  leech,  where  it  receives  the  tannic  principle,  and 
the  tan  vats  where  it  is  absorbed,  may  be  kept  up.  The 
reciprocating  motion  of  the  frames,  G  G,  of  the  tan 
vats  already  described  is  kept  up  during  the  tanning 
process. 

The  practical  advantages  derived  from  the  use  of  an 
apparatus  composed  of  a  series  of  air-tight  vessels  with 
air  pump  and  system  of  connection,  such  as  above  de¬ 
scribed,  are  as  follows:  It  is  well  known  to  tanners  that 
when  a  hide  is  limed  in  open  vessels,  and  frequently 
exposed  to  the  air,  it  becomes  so  hard  and  crusty  that 
in  order  to  soften  it  such  a  decomposing  beating  process 
is  necessary,  that  the  hide  is  brought  so  nearly  to  a 
putrefactive  condition  that  its  substance  is  materially 
changed,  and  it  is  not  unfrequently  seriously  damaged, 
and  it  is  also  well  known  that  in  using  tan  liquors  in 
open  vats,  the  liquor  readily  absorbs  the  oxygen  of  the 
air  and  the  tannic  acid  is  so  changed  to  gallic  acid,  which 
latter  not  possessing  any  tanning  property,  but  having 
a  dissolving  effect  on  the  fibre  of  the  hide,  thereby  dam¬ 
aging  its  textile  strength,  and  being  of  the  same  color 
as  tannic  acid,  is  a  dangerous  obstacle  in  the  way  of  suc¬ 
cessful  tanning;  on  the  contrary,  by  using  air-tight  vats 
for  liming,  the  change  and  loss  in  quality  of  the  lime 
liquor  is  avoided,  and  by  using  such  vats  for  tanning 
every  species  of  chemical  change  in  the  liquor  is  avoided ; 
and  in  bating  the  use  of  air-tight  vessels  is  of  no  less 
advantage,  as  it  permits  the  retention  of  all  of  the  free  am- 
moniacal  gases,  which  gases  perform  so  important  a  part 
in  facilitating  the  neutralizing  of  any  remaining  lime 
in  the  hide,  and  cleansing  the  cuticle  of  all  extraneous 
matter. 

By  the  use  of  the  reel  in  the  lime  tanks  the  positions 
of  the  hide  are  constantly  changing,  and  they  are  pre- 


TANNING  WHEEL. 


347 


sented  to  the  action  of  the  lime  liquor  to  the  best  ad¬ 
vantage,  the  hair  and  epidermis  being  loosened,  and  the 
hide  being  left  in  a  naturally  soft  condition  in  a  short 
space  of  time.  Corresponding  advantages  result  from 
the  use  of  the  reel  in  the  bate  vat,  and  in  the  handler 
by  the  use  of  the  reciprocating  frames  G,  in  the  tan  vats, 
the  hides  being  suspended  at  a  distance,  a  point  just 
sufficient  to  permit  the  circulation  of  the  tan  liquor 
between  them,  are  caused  to  be  brought  very  uniformly 
and  rapidly  into  contact  with  the  tan  liquor,  the  absorp¬ 
tion  of  which  is  thereby  accelerated. 

By  the  use  of  the  perforated  false  bottom,  with  in¬ 
clined  sides  in  the  leeches,  the  different  substances  are 
leeched  by  percolation,  by  which  means  from  15  to  25 
per  cent,  more  strength  can  be  obtained  from  tanning 
material  than  by  either  of  the  old  modes  of  maceration 
or  filtration. 


CHAPTER  LXXVIII. 

TANNING  WHEEL. 

This  new  apparatus,  invented  by  V.  E.  Rusco,  of 
Chicago,  was  patented  in  November,  1863,  and  has  been 
used  by  many  tanners,  who  consider  it  a  great  improve¬ 
ment. 


Fig.  100. 


348 


TANNING. 


Fig.  100  is  a  view  of  a  single  wheel.  Fig.  101  is  an 
end  view  of  the  same,  showing  the  internal  arrangement 


Fig.  101. 


of  the  wheel  and  the  hooks  by  which  the  leather  is  kept 
in  motion. 

Fig.  102  shows  how  a  number  of  wheels  may  be 
operated  by  one  shaft  and  pulley.  Any  number  of 
wheels  can  be  driven  in  this  manner,  and  each  one  can 
be  thrown  in  or  out  of  gear  by  means  of  a  clutch  and 
shipper. 

Fig.  103  shows  how  the  wheel  can  be  driven  by  a 
rope  without  the  expense  of  a  worm  shaft  and  segments. 
This  way  of  driving  will  answer  when  gear  cannot  be 
procured,  but  is  not  to  be  recommended  either  for  dura¬ 
bility  or  economy. 

Fig.  100  is  a  perforated  wooden  cylinder,  made  of 
staves  and  hooped  with  iron  bands;  the  ends  of  the 
cylinder  are  closed.  In  the  inside  of  the  cylinder  are 
wooden  hooks,  in  the  form  of  a  seekle,  which  keep  the 
leather  in  motion  as  the  wheel  revolves.  This  wheel  is 
best  driven  by  a  screw  pinion  working  in  a  segment 
placed  on  the  circumference,  and  when  but  one  wheel  is 
used  in  a  tannery  it  should  make  from  1|  to  2  revolu¬ 
tions  per  minute.  When  a  number  of  wheels  are  used 
a  slower  motion  is  desirable.  The  small  amount  of 
power  required  to  drive  this  wheel  is  greatly  in  its  favor. 


TANNING  WHEEL. 


349 


Fig.  102. 


No  more  power  is  required  to  operate  ten  of  these  wheels 
than  it  takes  to  operate  one  England  wheel.  The  wheel 
is  submerged  nearly  to  its  surface,  and  turning  with  a 
slow  and  regular  motion,  produces  plump,  firm,  and  yet 
very  soft  and  pliable  leather.  Many  first-class  tanners 
give  it  as  their  opinion  that  the  highest  speed  of  other 
wheels  makes  thinner  shoulders  and  flanks  than  is  made 
in  the  ordinary  way  of  tanning ;  while  in  the  submerged 
wheel  there  is  no  strain  to  draw  out  the  thin  parts  of 
the  leather. 

When  the  hides  are  ready  for  the  liquor,  they  are 
placed  in  the  wheel  through  trap-doors,  which  are  closed 
and  fastened.  About  300  calf-skins,  125  sides  of  upper, 


350 


TANNING, 


or  100  sides  of  harness  is  the  capacity  of  a  wheel,  such 
as  can  be  worked  in  a  vat  9  by  10,  5  feet  deep.  Par¬ 
ticular  attention  should  be  paid  to  running  the  liquor 
for  the  first  two  days  in  a  green  pack  to  draw  a  fine 


Fig.  103. 


grain.  The  third  run  of  a  leech  is  quite  strong  enough. 
The  vat  should  not  be  drawn  down  more  than  ten  inches 
at  a  time  two  or  three  times  a  day  for  the  first  two 
days.  Draw  the  leather  once  a  day  for  the  first  two 
days.  After,  increase  the  strength  and  quality  of  fresh 
liquor. 

After  running  a  few  days  in  the  wheel  the  leather 
may  be  laid  away  in  the  ordinary  manner.  When  laid 


NEW  MODE  OF  TANNING  SKINS. 


351 


a  proper  time,  it  may  be  returned  again  to  the  wheel 
with  great  advantage. 

Care  and  judgment  are  necessary  in  proportioning  the 
continual  increasing  strength  of  the  liquor  to  the  require¬ 
ment  of  the  leather  in  the  different  stages  of  this  pro¬ 
cess.  The  liquor  should  be  kept  cool,  never  to  exceed 
80°,  too  high  a  temperature  with  a  strong  liquor  being 
highly  injurious  to  the  life  of  the  leather.  It  is  well 
known  to  practical  tanners  that  a  certain  time  is  neces¬ 
sary  to  produce  a  certain  quality  of  leather.  It  is  claimed 
for  this  wheel  that  it  will  save  much  of  the  labor,  and 
greatly  lessen  the  time  in  the  ordinary  way  of  tanning. 
If  this  wheel  has  no  other  merit  than  coloring,  it  should 
recommend  it  to  all  tanners.  It  also  works  equally  well 
for  bating  and  liming.  Tanners  will  understand  that 
it  requires  a  larger  wheel  for  liming,  as  the  hides  full  up 
more. 


CHAP TEE  LXXIX. 

NEW  MODE  OF  TANNING  SKINS  BY  A  LIQUOR  OF  TAR 

AND  SOOT. 

Preparation  of  the  Tan  Liquor. — Take  100  gallons  of 
boiling  water  and  throw  into  it  from  18  to  20  pounds 
of  good  tar,  add  enough  lime  to  form  a  thick  paste. 
Pour  cold  water  on  to  this  composition,  to  precipitate 
the  lime  in  the  form  of  a  powder;  then  add  a  pailful  of 
tar  and  an  equal  quantity  of  powdered  lime ;  stir  until 
you  obtain  a  thick  paste. 

Distribute  this  composition  in  several  vats.  The  hot 
water  is  then  drawn  off  from  the  kettle  and  poured  in 
the  vats — being  careful  to  stir  the  composition  three  or 
four  times  with  a  shovel  while  you  pour  in  the  hot 
water.  When  the  water  is  thus  disturbed  cover  the 
vats,  and  twenty-four  hours  after  the  liquor  can  be  used. 

Preparation  of  the  Soot  Liquor. — In  a  kettle  for  every 
100  pounds  of  soot  pour  55  gallons  of  water  and  4 
pounds  of  powdered  lime;  stir  three  or  four  times  dur¬ 
ing  the  filling  of  the  kettle;  cover  this  kettle,  and  in 
twenty-four  hours  filter  the  liquor. 


352 


TANNING. 


Preparation  of  the  Skins  intended  for  Leather.— 
skins  destined  to  be  converted  into  polished  leather  are 
depilated  and  cleansed  by  the  ordinary  processes.  They 
are  then  put  in  cold  vats  of  oak-bark  paste,  and  left  in 
four  or  five  days,  and  even  a  week.  Handle  them  three 
or  four  times  a  day,  and  withdraw  them.  Dip  them 
afterwards  into  the  warm  tar  liquor  of  half  strength, 
and  increase  gradually  the  strength  until  it  has  reached 
the  primitive  degree.  Leave  them  fifteen  days  in  this 
liquor;  put  them  anew  in  the  oak  bark  as  the  first  time, 
then  in  the  weak  liquor  of  tar.  Handle  them  three  or 
four  times  a  day  for  the  first  two  weeks ;  place  them  in 
the  strong  liquor ;  handle  them  twice  a  day,  and  leave 
them  till  they  are  well  penetrated.  This  operation 
done,  the  skins  are  put,  for  a  week  or  more,  according 
to  their  thickness,  in  a  warm  solution  of  sumach.  With¬ 
draw  and  dry  them. 

Preparation  of  Leather  for  Soles. — The  hides  are  de¬ 
prived  of  hair  and  flesh  by  the  usual  process.  Put 
them  for  a  few  days  in  a  cold  vat  of  oak  bark.  Take 
them  out  and  dip  them  as  for  polished  leather ;  intro¬ 
duce  them  into  a  vat  containing  a  weak  and  warm  liquor 
of  soot — the  degree  of  strength  is  about  one-third  or 
one-half  of  the  primitive  liquor. 

The  skins  are  handled  three  or  four  times  a  day ;  put 
them  in  a  vat  containing  the  warm  liquor  with  all  its 
strength;  handle  them  three  or  "four  times  a  day  till 
well  impregnated ;  dry  them ;  dip  them  again,  for  half 
an  hour,  into  a  vat  containing  hot  water.  Brush  and 
wash  them  well. 

The  skins  thus  prepared  are  dipped  in  a  strong  solu¬ 
tion  of  oak  bark.  Handle  them  three  or  four  times  a 
day  until  the  operation  is  achieved.  Dry  the  skins 
every  time  they  have  been  dipped  in  the  last  liquor. 


hatch’s  process  of  tanning. 


353 


CHAPTER  LXXX. 

INDIAN  METHOD  OF  PREPARING  ELK-HIDES. 

Immediately  after  the  skin  is  taken  spread  it  to  dry ; 
take  out  the  brains  of  the  animal:  which  dry  in  the 
sun  on  the  grass.  When  the  hunting  season  is  over  the 
women  prepare  the  hides  by  soaking  them  first  in  water, 
and  afterwards  taking  off  the  hair  with  an  old  knife, 
and  putting  the  hides  in  a  large  earthen  vessel,  adding 
to  them  the  brains ;  then  heat  these  hides  to  about  95°, 
which  operation  cleans  them  very  well.  They  take 
the  skins  and  wring  them,  without  taking  out  the  water 
entirely ;  they  spread  them  on  a  kind  of  rack  composed 
of  two  perpendicular  posts  and  two  sticks  placed  hori¬ 
zontally.  With  ropes  they  spread  them  well,  and  during 
the  drying  they  rub  them  all  the  time  with  a  stone  or 
with  a  round  piece  of  wood  to  expel  the  water  and 
grease,  till  they  are  perfectly  dried.  The  operation  is 
then  completed. 

In  one  day  a  woman  can  prepare  from  eight  to  ten 
skins. 


CHAPTER  L XX X I . 

HATCH’S  PROCESS  OF  TANNING,  CALLED  ILLINOIS 
FRENCH  TANNING. 

We  mentioned  that  Mr.  Hatch,  of  Princetown,  Illi¬ 
nois,  has  taken  out  two  patents  for  his  process.  The 
first  was  patented  in  1856,  and  consists  in  preparing 
hides  and  transforming  them  into  leather  by  using 
smoke  of  wood  or  its  equivalent  combustible,  in  the 
following  manner: — 

The  nature  of  his  invention  consists  in  smoking  hides 
after  being  unhaired,  and  heated  previous  to  putting 
them  in  tan,  which  changes  the  nature  of  the  gelatine 
into  an  admirable  condition  for  the  rapid  absorption  of 
the  tannin,  and,  at  the  same  time,  preserving  the  full 
texture  and  strength  of  the  fibre,  thus  enabling  him  to 
23 


354 


TANNING. 


tan  calf-skins  in  from  two  to  twelve  days,  upper  and 
collar  leather  in  from  eight  to  twenty  days,  and  other 
leather  in  a  proportionate  time  according  to  the  thick¬ 
ness.  By  smoking  the  hides  and  then  handling  them 
in  sumach,  bran,  and  water,  for  half  a  day,  and  then 
putting  them  in  alum,  tan,  and  sumach,  the  tan  struck 
through  heavy  uppers  in  three  days. 

Hides  prepared  in  this  way  preserve  the  gelatine  in 
such  a  condition  as  to  keep  longer  in  even  poor  weak 
liquor  devoid  of  tan.  He  uses  smoke  from  various  kinds 
of  combustibles,  all  producing  the  same  effect. 

Some  of  the  great  beneficial  results  in  this  kind  of 
tanning  are  these :  With  a  small  capital  he  can  compete 
with  any  tanner  using  bark;  the  leather  is  better  and 
more  durable.  By  using  smoke  in  connection  with 
tannin,  it  enables  him  to  use  terra  japonica  with  or 
without  acids  in  the  tanning,  with  pretty  good  results. 
In  the  West,  where  no  bark  is  to  be  obtained,  he  can 
successfully  tan  in  much  less  time  than  in  tan  bark 
districts. 

That  this  principle  of  smoke,  the  great  desideratum, 
is  applicable  in  bark  tanning,  the  world  over  in  terra 
japonica,  or  other  tannin.  By  it  he  has  been  able  to 
bring  8  lbs.  of  prepared  hide  through  in  36  hours,  cow¬ 
hide,  upper  leather,  and  collar  leather  in  eight  days, 
making  good  leather,  yet  he  prefers  from  four  to  twelve 
days’  time  for  tanning  the  same. 

The  leather  tanned  by  this  process  has  been  well 
tested,  and  given  good  satisfaction.  The  method  of 
operating  is  as  follows :  The  hides  are  bated  in  the 
usual  way,  either  in  hen  bate,  or  wheat  bran,  as  it  leaves 
the  hides  more  plump,  until  the  lime  is  thoroughly 
worked  out ;  after  working  it  off  the  last  time,  they 
are  rinsed  in  clean  water  to  plump  up,  and  open  the 
hide  fully  wet,  in  order,  while  smoking,  the  grain  may 
not  become  dry,  as  well  as  to  rinse  off  all  uncleanliness ; 
then  hang  up  in  a  tight  smoke-room  sufficiently  large 
to  hang  up  by  but  and  neck,  grain  side  out,  then  make 
a  smoke  in  such  a  manner  that  the  hides  may  not 
become  heated  from  the  fire.  Smoke  upper  and  collar 


hatch’s  process  of  tanning. 


355 


leather  hides  six  hours,  other  hides,  time  according  to 
thickness,  then  take  them  out  and  soak  them  an  hour 
in  clean  water,  to  assure  the  hides  a  fully  wet  condition, 
before  coming  in  contact  with  tan  ;  then  put  them  in 
tan  ooze  of  moderate  strength.  Stir,  and  handle  often, 
until  the  grain  is  colored  even  and  struck  through,  then 
increase  the  strength  of  the  ooze,  by  tannin  from  day  to 
day,  until  the  hides  are  tanned. 

To  get  a  light  color  in  the  terra  japonica  or  hemlock 
ooze,  add  a  little  sumach  in  the  first,  handled  in  such 
proportion  as  half  a  pound  per  side  for  upper  leather. 

For  heavy  leather,  such  as  harness  and  sole-leather, 
after  being  prepared  in  the  usual  way,  should  be  smoked 
six  hours,  then  soaked  in  clean  water  one  hour,  then 
smoked  again  six  hours,  soaked  again,  and  passed  in 
tan  as  above  stated. 

As  regards  the  above  process  on  smoking ,  or  preparing 
hides  for  tanning ,  the  author  «ays:  “I  am  well  aware 
that  smoke  has  been  used  in  dressing  glove  leather,  out 
of  deer-skins  in  the  old  Indian  manner,  but  not  used  in 
the  manner,  and  for  the  purpose,  as  I  use  it  under  the 
patent,  namely,  in  preparing  hides  for  tanning ,  to  tan 
with  any  vegetable  tanning  astringent.” 

The  novel  application  of  smoke,  as  done  under  this 
patent,  has  the  following  great  and  desirable  effect  on 
hides:  It  toughens  the  epidermis,  retains  and  coagulates 
the  albumen,  permeates,  toughens  and  preserves  the 
gelatine  and  fibrin,  and  disposes  them  to  readily  unite 
with  tannin,  producing  leather  rapidly  and  of  great 
firmness.  It  also  plumps  up  the  flanks  and  shoulders  of 
leather,  causing  them  to  readily  fill  up  with  tannin ; 
therefore  much  better  weight  to  the  profit  of  the  tanner 
and  also  to  the  worker  of  leather;  as  they  are  enabled 
to  cut  out  more  solid,  serviceable  leather  than  is  gen¬ 
erally  obtained  from  old  fashioned  tanning.  The  leather 
also  generally  retains  its  pliability  and  smoothness 
longer  in  wear  through  all  kinds  of  weather.  The  tan 
liquors  also  become  impregnated  with  the  potent  prin¬ 
ciple,  and  are  thereby  rendered  in  preserved  condition  so 
that  they  do  not  sour,  thereby  a  great  saving  of  tannin. 


356 


TANNING. 


As  in  the  old  way  of  tanning  fresh  tan  liquors  are  often 
drawn  off  into  vats  of  sour  liquor,  or  the  latter  is  drawn 
off  into  leeches  of  pure  fresh  tan,  thereby  the  sour  liquor 
precipitates  a  portion  of  the  tannin  in  flakes  to  the 
bottom  of  the  vat;  in  this  manner  much  tannin  is  ut¬ 
terly  lost  to  the  tanner  and  the  country,  the  saving  of 
which  alone,  by  this  simple  and  almost  costless  improve¬ 
ment,  is  no  small  item.  Hides  but  slightly  tanned  have 
been  known  to  keep  a  long  time  in  a  perfectly  sound 
condition  in  such  impregnated  liquors  devoid  of  tannin, 
this  improvement  thus  preventing  damage  by  decompo¬ 
sition  of  hides  in  process  of  tanning,  when  the  tanner 
may  happen  to  be  deficient  in  supply  of  tanning  material. 

The  best  results  from  this  improvement  are  seen  in 
oak  bark  or  japonica  tanning.  This  system,  now  called 
Illinois  French  tanning ,  lately  reorganized  on  the  pre¬ 
vious  and  following  process,  reconstructed  and  .systema¬ 
tized  since  1858.  The  system,  as  now  organized,  having 
other  very  important  filings  in  ingredients  and  a  method 
not  here,  nor  ever  yet  made  public,  or  communicated  to 
any  but  the  purchasers  of  the  process. 

The  melilotus,  or  trefoil  plant,  mentioned  in  the  follow¬ 
ing  processes  a  very  useful  and  cheap  plant  in  tanning; 
it  is  a  substitute  for  the  imported  Sicily  sumach;  besides 
possessing  equal  and  similar  coloring  matter  it  also  pos¬ 
sesses  certain  saccharine  properties  that  sumach  does 
not  contain.  It  gives  valuable  conditions  to  leather,  a 
beautiful  oak  color,  softness,  toughness,  and  a  cheesy  con¬ 
dition  ;  it  rectifies  terra  japonica  in’ leather,  so  as  to 
modify  its  caustic  nature  and  entirely  do  away  with  the 
japonica  smell,  giving  leather  a  pleasant  aromatic  odor. 
The  proportion  of  the  plant  in  the  system  is  small;  it 
is  a  hardy,  rapid  growing  plant  on  low  damp  soil, 
yields  heavily,  producing  from  four  to  six  tons  per  acre, 
and  two  yearly  crops  from  one  seeding. 

All  other  cloves  or  grasses  have  a  weakening  effect  on 
leather,  causing  it  to  be  thin  and  flanky,  and  to  suffer  a 
great  loss  in  weight.  The  melilotus  in  effect  is  to  the 
reverse  of  all  that,  and  favors  all  the  desirable  conditions 
in  leather. 


IRISH  PROCESS. 


357 


This  new  process  was  patented  in  1861,  and  consists 
in  the  use  of  the  sweet-scented  clover  (Melilotus),  in  con¬ 
nection  with  terra  japonica,  cutch,  tan  bark,  or  other 
material  used  in  the  tanning  of  or  manufacture  of  leather. 
Mr.  Hatch  operates  as  follows:  He  extracts  the  virtue 
from  the  melilotus  by  steeping  in  water,  or  tan  liquor, 
and  mixes  the  same  with  the  terra  japonica,  cutch,  or 
other  tan  in  the  proportion  of  4  pounds  of  the  green,  or 
2  pounds  of  the  dry  plant  to  each  side  of  upper  leather, 
or  according  to  heavier  or  lighter  stock — measuring 
the  amount  of  melilotus  to  the  proportion  of  tan  used, 
as  greater  softness  or  toughness  of  leather  is  desired ;  or 
decreasing  the  proportion  of  melilotus  as  greater  firmness 
of  leather  is  desired.  Put  the  raw  hide  into  the  liquor 
of  said  melilotus,  and  tan  combined,  or  into  each  sepa¬ 
rately — changing  from  one  to  the  other  until  tanned ; 
and  also  drench  tan  leather  in  the  liquor  of  said  meli¬ 
lotus  to  soften  it,  and  likewise  to  improve  the  color  to 
that  of  oak-tanned  leather. 

The  plant  should  be  gathered  when  in  flower,  or  when 
about  going  into  flower. 

It  is  a  well-known  fact  that  terra  japonica,  and  cutch, 
are  powerful  astringents,  and  that,  used  alone,  they  tend  to 
make  leather  harsh  and  brittle,  and  thus  liable  soon  to 
crack  and  break  to  pieces  in  wear;  but,  using  the  meli¬ 
lotus  plant  in  connection  with  them,  has  an  admirable 
effect  in  neutralizing  their  harsh  nature,  and  thus  to  im¬ 
prove  their  condition  in  tanning  leather. 

CHAPTER  LXXXII. 

IRISH  PROCESS.  • 

In  1776  Mr.  Rankin  announced  that  the  heath,  which 
is  very  common  in  Ireland,  contained  a  tanning  prin¬ 
ciple  susceptible  of  taking  the  place  of  oak  bark.  Several 
experiments  having  succeeded,  he  published  the  follow¬ 
ing  process:  He  puts  the  heath  in' a  large  kettle  full  of 
water,  and  leaves  it  to  boil  three  hours,  which  time  is 
sufficient  to  exhaust  it.  He  decants  this  water  in  large 


358 


TANNING. 


vats  which  must  he  fixed  in  such  a  way  that  the  water 
can  be  exhausted  a  second  time.  Be  careful  to  put  the 
skin  in  this  last  water  when  the  temperature  has  fallen 
at  95°.  This  method  tans  the  skins  more  easily  than 
in  the  ordinary  process.  The  solution  of  heath  must 
be  changed  often;  and,  when  used,  the  temperature 
must  not  be  higher  than  95°.  This  process  gives  a  good 
tanning. 


CHAPTER  LX XX III. 

PROCESS  OF  MANUFACTURING  LEATHER  CALLED  CUIRS 

A  MURON. 

When  the  hides  are  fresh,  soak  them  for  eight  days 
in  particular  wells,  or  in  the  river;  draw  them  out  every 
day  to  soften  them.  When  they  have  been  sufficiently 
soaked,  take  them  out  and  put  them  in  a  solution  com¬ 
posed  of  two  parts  of  ashes  and  one  of  quicklime;  dis¬ 
solve  the  ashes  and  lime  by  boiling  water,  stirring  all 
the  time.  Afterwards  pour  this  mixture  in  a  vat,  dilute 
it  with  the  necessary  water,  and  soak  the  hides  in  it. 
Not  to  have  them  in  contact  with  the  residuum,  which 
always  settles  to  the  bottom,  cover  it  with  a  grate. 
Leave  the  hides  in  it  until  the  hair  can  be  pulled  easily, 
which  is  generally  the  case  after  eight  days.  Take  them 
out  and  depilate  them  with  the  round  knife.  Then  tie 
the  skins  two  by  two,  suspend  them  to  poles,  and  place 
them  in  a  current  of  water  to  cleanse  them  entirely  from 
ashes  and  lime.  Let  them  drain,  flesh  them,  and  tram¬ 
ple  upon  them  with  the  feet. 

The  small  hides  are  put  in  a  mixture  called  Jcakscha, 
composed  of  warm  water  and  dog  dung.  Leave  them 
to  soak  for  twenty-four  hours;  take  them  out,  clean,  and 
wash  them;  macerate  them  in  a  liquor  composed  of  oat 
flour  and  malt;  leave  them  twenty-four  hours.  Put 
them  in  tan  wafer,  where  they  stay  three  days;  after¬ 
wards  they  are  worked  in  the  following  manner:  Fill 
the  vat  half  with  pure  and  half  with  tan  water;  lay  the 
hides  on  the  grate,  after  having  covered  each  one  with 


KALMUCKS’  PROCESS. 


359 


powdered  oak  bark:  the  little  hides  may  remain  eight 
days ;  leave  the  strong  thick  ones  a  longer  time.  When 
you  draw  the  hides  empty  that  vat,  wash,  trample  the 
hides  with  the  feet,  wash,  and  flesh  them ;  repeat  the 
same  operation  four  times,  being  careful  to  cover  each 
time  the  skins  with  oak  bark;  the  fourth  time  leave  the 
skins  in  the  vat  for  three  weeks.  When  they  are  suf¬ 
ficiently  tanned,  they  are  spread  two  by  two,  and  as  soon 
as  they  are  dry  they  are  sent  to  the  currier. 

For  red  leather  they  generally  take  buckskins  and 
calf-skins  of  every  age.  The  red  leather  is  dyed  with 
red  sandal-wood,  and  the  black  with  logwood.  A  large 
skin  requires  1  lb.  of  sandal;  h  lb.  is  sufficient  for  a 
small  hide.  To  dye  100  hides  black,  dissolve  with  the 
logwood  3  lbs.  of  green  vitriol;  and  for  100  red  skins  3 
lbs.  of  alum.  Before  dyeing  the  skins,  give  them  the 
form  of  bags,  leaving  only  a  small  aperture  to  introduce 
the  dye;  shut  this  opening,  and-  shake  the  skin  in  in 
every  way.  This  done,  leave  the  skin  to  dry,  and  give 
it  a  second  and  even  a  third  dye.  When  the  skin  is 
colored  enough,  coat  it  on  the  flesh  side  with  birch  tan 
or  whale  oil. 


CHAPTER  LXXXIY. 

KALMUCKS’  PROCESS. 

With  the  Kalmucks,  the  women  have  the  charge  of 
tanning  the  hides.  To  prepare  the  skins  of  young  lambs, 
they  wash  them  in  tepid  water,  spread  them  in  the  open 
air,  and  keep  them  till  nearly  dried,  then  they  flesh 
them,  and  expose  them  anew  to  the  air  on  the  grass. 
During  three  days,  they  coat  them  three  times  a  day 
with  sour  milk,  in  which  a  little  salt  is  dissolved ;  the 
fourth  day  the  skins  are  dried,  and  are  worked  all  over 
with  the  hands,  until  entirely  supple. 

To  have  the  hides  resist  the  dampness  and  rain,  they 
are  smoked ;  for  this  purpose,  a  fire  is  lighted  in  a  little 
vat,  on  which  rotten  wood,  dry  manure,  etc.,  are  thrown. 
They  also  use  sheep  dung,  and  the  stipa  capillata. 


360 


TANNING. 


All  round  the  pit  they  plant  sticks  disposed  in  form 
of  pyramids,  which  are  covered  completely  with  the 
skins  destined  to  be  smoked.  From  time  to  time  the 
position  of  the  skins  is  changed  from  top  to  bottom. 
They  continue  thus,  for  one  hour,  then  they  work  them 
to  render  them  supple  ;  they  are  rubbed  on  the  flesh  side 
with  chalk,  or  gypsum ;  they  are  polished  with  knives, 
bleached  anew  with  chalk,  and  well  beaten. 

Buck,  and  sheep-skins,  destined  to  make  riding  pants, 
or  travelling  summer  dresses,  are  prepared  in  the  follow¬ 
ing  manner.  The  fresh  hides  are  rolled,  and  left  in  a 
corner,  until  the  wool,  or  hair,  can  be  pulled ;  they  are 
coated  with  sour  milk,  and  worked  in  the  same  manner 
as  lamb-skins ;  then  they  are  spread  on  the  ground,  and 
the  flesh  side  is  coated  with  a  strong  decoction  of  statice , 
to  which  alum,  and  a  certain  quantity  of  mutton  suet 
are  added,  then  they  are  dried.  Begin  again  the  opera¬ 
tion  until  the  color  of  the  root  has  exactly  penetrated 
the  skins.  The  hides  thus  prepared  resist  the  damp¬ 
ness  well. 

The  Kalmucks  who  live  on  fish,  skin  the  large  sea 
carp,  dry  the  skin,  remove  the  scales,  and  tan  it  after¬ 
wards.  For  this  purpose  they  use  sour  milk,  ora  decoc¬ 
tion  of  statice.  These  hides  are  almost  transparent,  and 
are  used  to  make  hoods  as  a  protection  against  the  rain. 

Nearly  all  the  house  utensils  of  the  Kalmucks  are 
made  from  leather.  For  this  purpose  they  use  ox,  and 
horse-hides.  The  back  part  is  considered  the  best.  To 
prepare  them,  they  heat  them  in  boiling  water  until  the 
hair  can  be  pulled  off,  others  depilate  them  with  ashes, 
afterwards  they  flesh,  and  wash  them  in  running  water. 
When  withdrawn  from  the  water,  they  are  spread  in  the 
sun.  Before  being  dried,  they  are  cut  into  pieces,  to 
which  the  intended  form  is  given,  and  those  pieces  are 
sewed  ;  the  form  is  then  given,  and  they  are  dried  before 
a  fire. 

Those  vessels  have  a  very  disagreeable  odor,  which 
communicates  to  everything  which  is  put  in.  They 
soften  by  the  introduction  of  a  liquid  too  cold  or  too 
warm.  These  defects  are  obviated  by  exposing  them  to 


LEATHER  MANUFACTURE  IN  TURKEY. 


361 


a  heavy  smoke  for  several  days  ;  by  this  means  they  take 
the  appearance  of  horn,  and  have  a  solidity  so  that  they 
can  be  kept  many  years  without  injury. 


CHAPTER  LXXXV. 

LEATHER  MANUFACTURE  IN  TURKEY. 

The  chief  manufacture  of  leather  in  Turkey  is  in  Tre- 
bizond,  Mosul,  Amaziah,  Constantinople,  and  Ternova. 
The  colored  goat  and  sheep-skins,  generally  used  to 
make  slippers,  come  from  Diarbeker,  Aleppo,  Damascus, 
Mecca,  Smyrna,  Sarohan,  Kutahiah,  Seras,  Uskuff, 
Salonica,  Philippopoli,  Tirhala,  Scyros,  Randos,  Eukare, 
Rustchuck,  Widden,  Constantinople,  and  Erzeroum. 
There  are  great  varieties  of  these  skins.  The  red  and 
the  yellow  are  brilliant  and  solid  ;  they  are  used  chiefly 
for  slippers,  especially  the  latter  color,  which  is  usually 
reserved  for  Turkish  ladies.  The  red  and  the  black  are 
much  sought  after  for  the  making  of  saddlery  of  the 
oriental  fashion. 

All  these  skins,  and  more  particularly  the  sleeked 
cow,  are  usually  a  little  too  dry ;  they  have  not  sufficient 
flexibility,  nor  are  they  thick  enough.  These  defects 
arise  chiefly  from  the  imperfect  tanning  processes  em¬ 
ployed  in  the  provinces.  The  sheep  and  goat-skins  are 
well  curried. 

It  is  known  that  the  European  process  of  tanning 
lasts  a  long  period.  None  of  the  attempts  made  in 
Europe  during  the  last  30  years  to  discover  means 
whereby  to  expedite  the  operation  of  tanning  have 
completely  succeeded.  The  hide  must  remain,  on  an 
average,  at  least  one  year  in  the  pit  before  it  becomes 
properly  tanned,  and  the  preparatory  operations  to 
which  the  hides  must  be  subjected  before  the  process  of 
tanning  is  entered  upon  are  also  quite  long  and  compli¬ 
cated.  They  are  divided  into  cleansing,  swelling,  depi- 
lation,  and  table  work.  Then  comes  the  operation  in 
the  vats  and  pits. 

A  tannery  is  built  quite  close  to  a  river,  or  to  a 


362 


TANNING. 


spring  of  water  able  to  furnish  all  the  water  necessary 
in  these  various  operations. 

The  hides  are  first  of  all  carried  to  a  river  and  plunged 
in  the  water  during  half  a  day  in  order  to  wash  away 
the  blood  and  dirt  with  which  they  are  soiled.  Care  is 
taken  to  turn  and  stir  them  from  time  to  time,  and  they 
are  rinsed  before  being  taken  out  of  the  water.  Dry 
hides,  of  course,  need  to  remain  longer  in  the  water 
than  fresh  skins.  These  are  briskly  washed  several 
times  each  day,  and  they  are  stretched  with  the  stretch¬ 
ing  iron,  trampled  under  the  feet,  cleansed,  and  the 
water  then  allowed  to  drain  off.  They  are  also  worked 
once  or  twice  at  least  with  a  round  knife,  having  no 
edge,  in  order  to  stretch  them  perfectly,  and  to  clean 
and  soften  them,  the  fleshing  having  been  previously 
done;  cellular  tissue,  the  viscous  matter,  the  muscular 
fibres,  and  in  general  all  those  parts  which  are  apt  to 
putrefy  readily,  are  removed. 

After  the  skins  have  been  sufficiently  softened  they 
are  replaced  in  the  water  and  allowed  to  remain  there 
from  five  to  six  hours.  Care  is  taken  not  to  let  them 
remain  too  long,  especially  if  the  water  is  not  fresh  and 
running,  for  too  long  a  stay  in  the  water  brings  about  a 
putrid  decomposition  of  the  hide,  which  affects  it  more 
or  less  deeply.  However,  all  species  of  water  are  equally 
suitable  for  this  operation,  provided  that  the  hide  is  only 
left  therein  long  enough  to  wash  it  thoroughly,  the  sole 
object  being  to  cleanse  it  and  remove  all  hardness  and 
stiffness.  It  has  been  ascertained  by  experience  that 
hard  water  is  more  suitable  when  heavy  leather  is  to  be 
produced,  and  soft  water  for  soft  leather. 

The  second  operation  to  which  hides  are  subjected  is 
the  swelling  or  raising.  The  method  used  in  the  Otto¬ 
man  provinces  is  a  preparation  of  barley  in  a  warm  vat. 
According  to  this  method,  as  soon  as  the  hides  have 
been  softened  in  the  water  they  are  trampled  under  the 
feet,  and  the  round  knife,  above  mentioned,  is  passed 
over  the  flesh  side  to  make  them  supple.  Then  they 
are  cleaned  and  placed  on  poles  to  drain.  They  are  next 
examined  to  ascertain  whether  the  hair  comes  off  readily 


LEATHER  MANUFACTURE  IN  TURKEY. 


363 


from  the  skin,  which  may  appear  in  summer  without 
further  preparation.  When  fresh  hides  are  treated  they 
salt  them  without  soaking  them  by  sprinkling  them 
with  about  5i  lbs.  of  a  mixture  made  up  of  sea  salt, 
alum,  and  saltpetre.  Then  they  pile  them  up  and  lay  a 
mat  over  them. 

Hides  thus  arranged  speedily  become  heated,  and 
they  are  turned  over  several  times  each  day  so  that  the 
fermentation  may  take  place  uniformly  in  all  parts,  and 
when  it  is  perceived  that  the  hair  will  come  off  easily  it 
is  at  once  removed,  as  a  too  prolonged  fermentation  will 
damage  the  flesh  side  of  the  hide. 

As  soon  as  the  depilation  is  completed  the  swelling 
is  begun.  For  this  purpose  they  make  a  leaven  of  wheat 
which  is  securely  covered  and  kept  in  a  warm  place.  It 
takes  24  hours  to  prepare  this  leaven.  In  swelling  the 
hides  a  vat  is  used,  which  is  partly  filled  with  water. 
Then  a  few  pailfuls  are  drawn  from  it  and  boiled,  and 
in  this  boiling  water  are  mixed  681  lbs.  of  barley, 
coarsely  ground,  made  into  a  paste  of  the  consistence  of 
a  thick  glue  by  the  admixture  of  cold  water;  then  they 
put  the  paste  back  into  the  boiler  and  let  it  boil  tho¬ 
roughly,  stirring  it  incessantly  with  a  stick.  After  it 
has  risen  three  times  they  pour  it  into  the  vat  and  stir 
the  contents  with  a  wooden  shovel,  turning  always  to 
the  one  side. 

The  vat  is  then  very  carefully  covered  after  having 
taken  out  two  pailfuls  of  the  liquid  that  it  contains, 
which  is  placed  on  the  fire,  and  as  soon  as  this  composi¬ 
tion  begins  to  bubble  they  mix  in  the  wheat  leaven  first 
made  and  pour  the  whole  into  the  vat.  This  constitutes 
the  first  operation,  which  is  intended  to  do  for  6  or  7 
hides.  Such  a  temperature  should  be  maintained  that 
the  workman  cannot  bear  his  arm  in  it  without  pain. 
They  then  add  5£  lbs.  of  sea  salt;  mix  the  whole  well 
together,  and  let  it  sour  during  15  days,  taking  care  to 
stir  it  several  times  each  day,  and  to  cover  up  the  vat 
again  immediately  thereafter  so  that  it  may  lose  none 
of  its  heat. 

At  the  end  of  that  time  the  hides  are  thrown  into  a 


364 


TANNING. 


spring  together  by  threes  on  a  rope,  and  they  are  left 
there  from  four  to  five  days.  Each  day  they  are  taken 
out  twice,  rinsed,  drained  a  little,  and  then  put  back ; 
and  this  operation  is  kept  up  until  the  flesh  side  of  the 
hide  becomes  soft  enough  to  retain  the  imprint  of  a 
finger  nail,  when  the  finger  is  pressed  against  it.  They 
are  then  taken  out  to  be  fleshed,  and  if  any  hair  remains 
it  is  shaved  off,  after  which  they  are  rinsed  in  clean 
water  and  laid  to  drain  upon  poles  during  twenty-four 
hours. 

A  second  leaven  of  wheat  is  then  made,  a  little 
weaker  thair  the  first.  The  sour  liquor,  which  was  used 
in  the  first  operation,  is  next  poured  out,  keeping  only 
the  clear  portion  of  the  liquid,  which  is  poured  into  a 
second  vat  in  order  to  receive  its  complement;  that  is 
to  say,  the  addition,  as  in  the  first  operation,  first  of  a 
quantity  of  ground  barley,  a  little  less  than  the  first, 
then  of  the  second  leaven  already  prepared,  and  finally 
of  a  little  sea  salt.  Thus  two  vats  are  prepared  for  the 
operation.  Care  is  taken  to  withdraw  a  few  pailfuls, 
which  are  kept  in  reserve  on  the  fire ;  and  when  the 
fermentation  is  well  established,  which  is  ascertained  by 
the  sourness  of  the  water,  the  hides  are  removed  from 
the  framework  of  poles  to  plunge  them  in,  for  a  minute 
or  two,  that  they  may  gradually  acquire  the  temperature 
of  the  vat.  They  are  then  laid  on  the  cover  of  the  vat 
so  that  they  may  drain  off  a  few  minutes  without  be¬ 
coming  cold ;  then  they  are  pressed  down  into  the  vat, 
and  after  it  is  covered  again  the  heat  is  kept  up  by  the 
aid  of  the  hot  water  held  in  reserve.  At  the  end  of  a 
quarter  of  an  hour,  the  hides  are  taken  out  for  the 
second  time,  and  are  allowed  to  drain  in  the  same 
manner  as  before  during  a  quarter  of  an  hour,  after 
which  time  they  are  again  plunged  into  the  vat  and  left 
there  half  an  hour. 


hannoye’s  process. 


365 


CHAPTER  LXXXYL 

J.  HANNOYE’S  PROCESS. 

Another  method,  analogous  in  principle  to  the  preced¬ 
ing,  consists  in  producing  an  equable  and  active  filtra¬ 
tion  of  tan-liquors  through  the  skins,  while  they  are  ex¬ 
posed  to  pressure,  the  kind,  temperature,  strength,  and 
mode  of  employment  of  which  can  be  varied  at  will. 
For  this  purpose,  the  filter-press  of  Real,  with  some 
modifications,  is  made  use  of,  not  merely  with  the  inten¬ 
tion  for  which  it  has  before  this  been  employed,  of  ex¬ 
tracting  the  active  principles  of  bark,  but  as  a  direct 
agent  in  the  tanning  process  itself;  the  skins  being  stra¬ 
tified  in  it  with  layers  of  bark,  and  the  extraction  of 
the  tannin,  and  the  absorption  of  it  by  the  skins,  being 
both  effected  under  pressure,  and  without  contact  of  air. 
The  apparatus,  which  has  been  prepared  upon  the  prin¬ 
ciple  of  the  filter-press,  is  provided,  like  it,  with  a  tube 
having  air-tight  joints,  by  means  of  which  a  forced  and 
uniform  filtration  is  effected  by  the  pressure  of  a  column 
of  fluid,  and,  the  tube  is  of  such  a  height  that  the  pres¬ 
sure  can  be  increased  or  diminished  at  pleasure  by  alter¬ 
ing  the  height  of  the  column,  while  the  character  of  the 
operation  can  be  varied  at  will  by  the  employment  of 
different  fluids.  The  pressure  of  the  column  of  fluid 
can  be  directed  alternately  upon  either  the  upper  or 
lower  surfaces  of  the  skins,  by  means  of  tubes  provided 
with  stopcocks,  and  entering  the  vessel  at  the  top  and 
bottom. 

The  inventor  claims  this  new  application  of  the  prin¬ 
ciple  of  the  filter-press,  as  being  entirely  original,  and 
asserts  that,  by  the  employment  of  it,  he  has  been  able 
to  arrive  at  a  perfection,  rapidity,  and  exactitude  of  the 
method  of  tanning,  which  have  not  been  attained  by  any 
other  process. 

Figs.  104, 105, 106.  Vessels  of  a  cylindrical  or  square 
form,  of  a  suitable  capacity  to  hold  the  number  of  skins 
intended  to  be  operated  upon,  and  which  are  capable  of 


366 


TANNING 


resisting  a  considerable  pressure.  A  tube  a,  a ,  Fig.  104, 
is  attached  to  each,  and  is  proportioned  in  height  to  the 


Fig.  104. 


mode  of  making  pressure  which  is  to  be  adopted,  whether 
it  be  that  of  a  column  of  watery  fluid,  of  mercury,  or  of 
the  hydraulic  piston.  Branch-pipes  b,  b\. connect  this 
tube  with  the  upper  and  the  lower  part  of  the  reservoir, 


Fig.  105. 


r 

T 

IL 

J 

K1 


1L 


Effi 


nr 


H 

1 

u 

u 

jfl 

II 


ii 


1JJ 

u 


i ii 


and  the  opening  of  one  or  the  other  of  the  stopcocks 
upon  them  causes  the  pressure  and  consequent  infiltra¬ 
tion  of  tan-liquor  through  the  skins  to  take  place  either 
from  above  downwards,  or  in  the  opposite  direction.  A 


hannoye’s  process. 


361 


Fig.106. 


pipe  with  a  stopcock  e,  allows  the  liquid  within  the  vat 
to  escape. 

“The  reservoir  may  be  composed  of  different  materials. 
It  may  be  constructed  of  solid  masonry,  covered  in  its 
interior  with  lime  cement,  over  which  a  coating  of  tar 
or  of  some  resinous  substance  is  placed,  so  as  to  defend 
the  leather  from  the  action  of  the  lime.  It  may  be 
made  of  wood,  lined  with  sheet  lead ;  zinc  or  copper,  well 
soldered  in  all  parts ;  or  may  be  composed  of  cast-iron, 
lined  throughout  with  lead  or  zinc,  so  as  to  prevent  the 
injurious  effect  of  oxide  of  iron  upon  the  leather.  In 
either  case,  the  rim  of  the  neck  of  the  vessels  consists  of 
a  solid  plate  or  disk  of  metal,  firmly  attached  to  it,  and  a 
disk  of  thick  leather  is  interposed  between  it  and  the 
top  or  lid,  which  is  tightly  fastened  down  by  means  of 
screws  and  nuts  upon  the  plate.  This  top  may  consist 
of  thick  wood  or  of  metal  plate,  also  lined  on  its  lower 
surface  with  sheet-lead  or  zinc.  The  copper  or  leaden 
tube  d ,  d ,  for  the  column  of  fluid,  is  from  one  to  three 
inches  in  diameter,  and  is  connected  with  the  vessels  by 
two  tubes  f,  f\  one  entering  it  below  the  lid,  the  other 
at  its  base.  By  opening  the  stop-cock  upon  the  upper 
tube,  the  pressure  of  the  fluid  is  made  upon  the  upper 
surface  of  the  skins,  and  in  the  opposite  direction  by 


368 


TANNING. 


opening  that  upon  the  lower  tube.  Two  other  cocks  g , 
g',  the  one  proceeding  from  the  lid,  the  other  from  the 
lower  part  of  the  reservoir,  conduct  the  liquid  which  has 
traversed  the  skins  into  a  suitable  receptacle,  the  upper 
one  being  left  open  when  the  pressure  is  from  below, 
and  the  lower  one  when  it  proceeds  from  above.  The 
skins  are  stratified  in  the  vat  between  beds  of  tan  ;  water 
alone  is  usually  employed  for  the  pressure  upon  its  con¬ 
tents,  and  for  the  extraction  of  the  tannin,  and  the  cocks 
for  the  egress  of  fluid  are  only  left  so  much  open  as  to 
allow  it  to  escape  drop  by  drop. 

“Calf-skins  may  be  tanned  in  twenty  days  by  this 
method,  and  ox-hides  in  sixty  days,  but  the  tanning 
may  be  much  expedited  by  the  following  arrangement: 
Instead  of  simply  stratifying  the  skins  with  layers  of 
bark,  a  framework  of  wood,  with  an  open  space  in  its 
interior,  rather  smaller  than  the  skins,  is  placed  upon 
each  one.  The  interior  of  this  frame  is  filled  with  tan, 
another  skin  is  extended  above  the  frame  thus  filled, 
and  is  in  turn  surmounted  by  other  frames  and  skins 
arranged  in  the  same  manner.  To  prevent  the  fluid 
from  being  forced  through  the  spaces  between  the  out¬ 
sides  of  the  frames  and  the  walls  of  the  vessel,  these  are 
filled  up  with  mastic,  or  some  impervious  cement  like 
the  fatty  lute  of  chemists,  or  a  mixture  of  tallow  and 
rosin.  A  similar  application  of  lute  is  made  around  the 
edges  of  the  skins,  and  the  weight  of  the  tan  and  frames 
soon  makes  the  cemented  parts  perfectly  tight. 

“  After  each  tanning  is  completed,  the  mastic  or  luting 
can  be  taken  off  and  used  for  a  similar  purpose  again. 
Skins  tanned  by  this  last  method  are  as  perfectly  pre¬ 
pared  in  a  few  days,  as  those  which  have  been  exposed 
in  the  pits  for  sixteen  months.” 

CHAPTER  LXXXVII. 

N.  NOSSITER’S  PROCESS.  t 

This  new  method  was  patented  in  England  in  1844, 
and  consists  in  depositing  the  skins  in  pits  so  that  they 


nossiter’s  process. 


369 


shall  not  be  subjected  to  the  pressure  of  those  placed 
above  them,  and  in  pressing  out  the  exhausted  infusion 
contained  in  them,  before  immersing  them  again  in  fresh 
ooze. 

1.  The  skins  being  superposed,  in  the  old  method  of 
tanning  in  vats,  those  which  are  below  are  so  compressed 
that  the  tan-liquor  penetrates  their  structure  with  diffi¬ 
culty.  To  avoid  this  objection,  the  inventor  proposes  to 
deposit  the  skins  in  square  vats,  and  to  separate  them  by 
the  interposition  of  rectangular  frames  with  ledges.  By 
this  means  the  skins  are  perfectly  free  from  contact  with 
each  other  while  in  the  tan-liquor. 

Fig.  107  represents  a  horizontal  section  of  the  vat,  and 
a  frame  with  a  skin  stretched  over  it. 

Fig.  10b 


Fig.  108,  is  a  vertical  section,  showing  the  frames  in 
stack,  and  the  skins  between  them. 


Fig.  109  shows  the  plan  of  the  bottom  of  the  vat. 
Fig.  110,  plan  of  the  frame. 

a,  a.  Vat,  of  the  ordinary  form;  6,  b,  wooden  frame, 


24 


370 


TANNING. 


Fig.  109. 


Fig.  110. 


with  crosspieces;  b\  ledges  for  maintaining  the  pieces  in 
position. 

This  method  of  tanning  is  much  more  expeditious 
than  the  old  way ;  for  although  fewer  skins  can  be  tanned 
by  it  at  one  time,  it  admits  the  working  of  a  greater 
number  in  a  given  time,  and  in  the  same  vat. 

The  vat  is  first  filled  with  the  skins  and  frames,  and 
the  tan-liquor  is  then  introduced.  When  this  latter  is 
exhausted  or  weakened,  it  is  pumped  out  and  replaced 
by  fresh  ooze. 

The  skins  are  deprived  of  exhausted  liquor,  in  many 
establishments,  by  pressure  between  rollers;  but  as  this 
method  does  not  fully  effect  the  object,  Nossiter  subjects 
them  to  the  action  of  a  screw-press,  which  is  seen  in 
vertical  section  in  Fig.  Ill,  and  in  the  plan,  Fig.  112. 
This  press  consists  of  a  strong  rectangular  support  f  ’ 
from  the  four  corners  of  which  arches  spring,  which 
meet  in  the  centre  in  a  square  nut  h,  in  which  the  strong 
screw  i,  turns.  The  skins  are  placed  above  each  other 
on  the  table  of  the  frame,  and  are  pressed  by  the  plate 
A-,  at  the  lower  end  of  the  screw,  which  is  turned  by  the 


nossiter’s  process. 


371 


Fig.  111. 


lever  l.  The  skins  are  subjected  to  this  pressure  until 
all  their  fluid  contents  are  expelled. 


Fig.  112. 


In  place  of  the  screw-press,  one  with  an  axle,  seen  in 
Fig.  113  in  vertical  section,  and  in  Fig.  114  in  plan,  may 


Fig.  113. 


be  used.  Around  the  axle  m,  the  cords  n,  n,  are  rolled, 
which  pass  through  pulleys  in  the  supports.  The  cords 
are  passed  at  their  ends  through  screw-rings  on  the  sides 
of  the  under  surface  of  the  plate  p.  By  turning  the 


372 


TANNING. 


Fig.  114. 


axle  with  the  lever  q ,  the  upper  plate  is  made  to  com¬ 
press  the  skins  which  are  placed  below  it. 

CHAPTER  LXXXV  III. 

SQUIRE’S  PROCESS.  - 

This  process,  patented  in  1844,  consists  in  depositing 
the  skins  in  a  horizontal  wooden  cylinder,  which  is  made 
to  revolve  slowly,  under  the  surface  of  hot  tan-liquor,  so 
as  to  insure  constant  agitation  of  the  hides  and  skins, 
and  perfect  exclusion  of  air. 

Fig.  115  represents  a  transverse  vertical  section  of  the 


Fig.  115. 


apparatus,  as  placed  in  the  vat:  a,  wooden  drum  12  feet 
long  and  7  feet  in  diameter,  lined  with  ridges,  and  di¬ 
vided  into  four  compartments  by  the  partitions  5,  b, 


PROCESS  TO  TAN  NETS,  SAILS,  AND  ROPES.  373 


which  are  composed  of  wooden  staves,  or  bars  with  open 
spaces  between  them.  Hot  ooze,  and  some  of  the  tan¬ 
ning  material  are  then  introduced  with  the  prepared 
hides  through  a  water-tight  door  c.  The  vat  should  be 
deep  enough  to  admit  the  submersion  of  the  whole  cyl¬ 
inder,  which  is  to  be  kept  in  uninterrupted  motion,  at 
the  rate  of  six  or  seven  revolutions  per  minute ;  and  for 
this  purpose  its  axle  d,  resting  upon  upright  supports, 
is  turned. 

This  is  really  an  accelerating  process,  for  the  use  of 
hot  ooze,  and  the  continuous  contact  of  the  skins  with 
the  tan  liquor,  shorten  the  time  for  complete  tanning  to 
two  weeks.  Moreover,  it  permits  the  use  of  divi-divi, 
catechu,  and  other  readily  oxidizable  tanning  materials, 
which,  when  used  in  open  vats,  color  the  leather  and 
render  it  unsalable.  The  access  of  air  in  this  process 
being  limited,  this  disadvantage  is  avoided. 

The  ooze  spends  its  force  very  rapidly,  and  must  be 
replaced  by  fresh  hot  liquor  as  fast  as  it  becomes  ex¬ 
hausted. 


CHAPTER  LXXXIX. 

ENGLISH  PROCESS  FOR  TANNING  NETS,  SAILS,  AND 

ROPES. 

The  following  method  of  preserving,  and  increasing 
the  strength  of  nets,  sails,  and  ropes,  has  been  proposed 
by  a  ship  builder  of  Bridgeport.  He  boils,  in  89  galls, 
of  water,  100  lbs.  of  oak  branches,  and  the  same  quan¬ 
tity  of  tan,  until  it  is  reduced  to  71  galls.  He  decants 
the  clear  liquid,  and  introduces  into  it  the  articles  to  be 
tanned,  being  careful  to  have  them  entirely  covered,  and 
not  touching  the  bottom  of  the  vessels.  lie  boils  them 
three  hours,  withdraws,  and  dries  them. 

This  is  not  a  regular  tanning  process ;  its  object  is 
only  to  combine  the  tannic  and  extractive  matter  with 
vegetable  substances,  which  are  very  different  from  the 
gelatine  of  the  skin.  Linen,  steeped  two  or  three  days 
in  a  solution  of  oak  bark  at  the  temperature  of  150°, 


374 


TANNING. 


was  kept  in  a  damp  cellar  for  ten  years,  without  being 
rotted,  while  an  untanned  piece,  placed  in  the  same  cir¬ 
cumstances,  was  completely  rotted. 


CHAPTER  XC. 

EXPERIMENTS  IN  THE  TANNING  OF  CALF-SKINS  WITH 
TAN,  DIVI-DIVI,  CATECHU,  AND  ELECAMPANE  BARK, 
BY  M.  KAMPFFMEYER. 

These  interesting  experiments  were  published  in  the 
Memoir es  of  the  Societe  <T Encouragement  of  Berlin ,  and 
the  Technologist.  We  shall  describe  them  with  details. 

To  proceed  to  these  experiments,  twenty-five  calf-skins 
were  chosen ;  they  were  identical  as  nearly  as  possible. 
Of  these  twenty-five  skins,  seven  were  tanned  with  oak 
bark,  six  with  the  elecampane  bark,  six  with  catechu, 
and  six  with  the  divi-divi. 

The  twenty-five  hides,  during  the  operations,  were 
submitted  to  the  same  manipulations.  When  those 
manipulations  were  finished,  all  the  skins  treated  by  the 
sulphuret  of  calcium  and  by  the  lime  were  cleansed  as 
much  as  possible  from  the  lime,  and  deposited  in  the 
vats. 

Oak  Bark. — Amongst  the  skins  tanned  with  this 
bark  the  three  pieces  treated  with  sulphuret  of  calcium 
weighed,  when  raw,  12  lbs.  14  oz. ;  weighed  anew,  after 
the  tanning,  and  passed  to  the  tallow,  they  weighed  12 
lbs.  5  oz.,  consequently  they  had  lost  9  oz.  There  had 
been  used  84  lbs.  2  oz.  of  bark ;  that  is,  6  lbs.  8£  oz.  of 
tan  per  pound. 

The  four  skins  treated  by  caustic  lime  weighed,  when 
raw,  14  lbs.  11  oz. ;  after  tanning  they  weighed  13  lbs. 
14  ounces,  consequently  they  had  lost  13  oz.  They 
required  107  lbs.  12b  oz.  of  tan;  that  is,  5  lbs.  81  oz. 
per  pound.  They  were  similar  to  the  commercial  lea¬ 
ther,  and  their  grain  was  finer  than  in  the  other  expe¬ 
riments. 

The  skins  treated  by  sulphuret  of  calcium  were  firmer 
and  soft. 


kampffmeyer’s  process. 


375 


Divi-Divi. — The  three  skins  treated  by  the  sulphuret 
of  calcium  weighed,  raw,  12  lbs.;  when  tanned,  they 
weighed  11  lbs.  3  oz.  ;  they  had  lost  9  oz.  They  re¬ 
quired  13  lbs.  2  oz.  of  divi-divi;  that  is,  1  lb.  lli  oz. 
per  pound. 

The  three  skins  treated  by  caustic  lime  weighed,  raw, 
10  lbs.  8  oz. ;  and  when  tanned,  9  lbs.  15  oz. ;  they  had 
lost  9  oz.  They  had  required  11  lbs.  3  oz.  of  divi-divi, 
or  1  lb.  Ill  oz.  per  pound. 

The  edge  and  the  color  were  very  fine,  and  the  tanning 
more  satisfactory  than  in  the  other  skins.  The  grain 
had  not  so  fine  an  aspect  as  the  skins  tanned  with  oak, 
but  it  was  satisfactory. 

Catechu  ( Terra  Japonica). — The  three  skins  treated  by 
sulphuret  of  calcium  weighed  9  lbs.  10  oz. ;  and  after 
tanning,  11  lbs.  13  oz. ;  they  had  thus  gained  2  lbs.  3 
oz.  They  required  13  lbs.  11  oz.  of  catechu,  or  1  lb.  21 
oz.  per  pound. 

The  three  other  skins  treated  by  lime  weighed  12 
lbs.;  when  tanned,  they  weighed  12  lbs.  41  oz.  They 
had  gained  41  oz.  They  required  13  lbs.  11  oz.  of 
catechu,  or  1  lb.  41  oz.  per  pound. 

The  tanning  was  perfect ;  the  color  slightly  orange ; 
the  side  was  equal  and  rough ;  the  grain  was  thin  and 
spongy  in  the  skins  treated  by  quicklime.  They  were 
inferior  to  the  others. 

Elecampane  Bark. — The  three  skins  treated  by  sul¬ 
phuret  of  calcium  weighed,  raw,  11  lbs.;  and  when 
tanned,  11  lbs.  41  oz. ;  they  had  gained  41  oz.  They 
required  155  lbs.  3  oz.  of  bark;  that  is,  14  lbs.  11  oz. 
per  pound. 

The  three  skins  treated  by  quicklime  weighed,  raw, 
10  lbs.  1  oz. ;  and  when  tanned  9  lbs.  101  oz. ;  they  had 
lost  6  oz.  They  had  required  121  lbs.  51  oz.  of  bark, 
or  6  lbs.  2  oz.  per  pound. 

Notwithstanding  the  large  quantity  of  bark,  the 
skins  were  more  or  less  imperfectly  tanned — principally 
those  treated  by  the  sulphuret  of  calcium ;  they  were 
so  hard  and  dense  that  the  grease  could  not  penetrate 
them  entirely  ;  the  grain  was  flat.  The  skins  could  be 


376 


TANNING. 


tanned  easily  even  after  the  greasing;  their  color  was 
brown. 

We  see  by  the  above  experiments  that  the  tanning 
with  oak  bark  and  divi-divi  were  the  best,  and  the  latter 
can  be  compared  with  the  oak. 

The  use  of  catechu,  as  a  dry  matter  in  the  tanning  of 
skins,  is  inadmissible.  The  porous  and  thin  texture  of 
the  leather  thus  manufactured  is  a  poor  guarantee  against 
dampness  and  permits  of  little  duration. 

The  results  obtained  with  the  elecampane  bark  are 
less  satisfactory. 

For  the  expenses,  there  is  little  difference  between 
oak  bark  and  divi-divi.  Divi-divi,  it  is  true,  is  more 
costly  ;  but  as  it  possesses  six  times  as  much  tannin 
as  oak  bark,  the  balance  will  be  rather  in  favor  of  the 
latter. 

Trials  were  also  made  with  green  Buenos-Ayres  hides, 
and  the  result  was  about  the  same  as  above.  The  divi- 
divi  is  superior  to  catechu  and  elecampane,  and  can  be 
compared  to  the  oak  in  many  respects  ;  but  it  requires 
more  care  in  its  use  on  a  large  scale,  while  the  operation 
is  one-third  shorter. 

According  to  the  author,  the  divi-divi  is  the  best  sub¬ 
stitute  for  oak ;  and  while  it  is  difficult  to  grind  it, 
reduced  into  the  form  of  an  extract,  it  can  be  advan¬ 
tageously  employed  by  its  mixture  with  oak  bark. 


CHAPTER  XCI. 

TANNING  HIDES,  BY  J.  W.  JOHNSON. 

Mr.  J.  W.  Johnson  proposes  to  employ  for  the  pur¬ 
pose  of  tanning  hides  a  new  vegetable  decoction  pre¬ 
pared  from  Maruta  Cotuln ,  to  a  gallon  of  which  are 
added  4  ounces  of  catechu  and  2  ounces  each  of  common 
salt  and  alum.  In  this  mixed  tan  liquor,  the  skins  or 
hides,  with  or  without  hair  upon  them,  are  to  be  im¬ 
mersed,  and  there  left  for  a  period  determined  by  the 
thickness  of  the  hide,  and  by  other  circumstances  which 
ordinary  experience  will  dictate. 


Turnbull’s  process. 


377 


Sir  Humphrey  Davy  was  the  first  to  show  that  catechu 
alone  could  be  employed  as  a  tanning  material.  We 
are  unacquainted  with  any  special  property  possessed 
by  the  vegetable  decoction  referred  to,  which  would 
render  advantageous  its  employment  in  conjunction  with 
the  foregoing. 


CHAPTER  XCII. 

'  TURNBULL’S  PROCESS. 

The  Technologist *  has  given,  on  this  process  of  tan¬ 
ning,  details  that  we  propose  to  reproduce  here. 

In  the  tanning  of  skins,  as  every  one  knows,  it  is  very 
difficult  to  bring  the  tannin  immediately  in  contact  with 
the  gelatinous  matter  of  the  skins,  and  that  for  the 
following  causes : — 

1.  Hides  macerated  in  lime  absorb  a  certain  quantity 
of  this  earth,  which  takes  a  portion  of  the  gelatinous 
substance  in  form  of  soluble  gelatine,  that  is,  alters  the 
fibre  enough  to  render  it  incapable  of  combining  effica¬ 
ciously  with  tannin,  and  the  pores  of  the  skin  are  so 
impregnated  with  lime  that  the  tanning  principle  cannot 
operate  freely  and  penetrate  to  the  heart  of  the  skin. 

2.  When  catechu  is  used,  the  leather  produced  is  very 
permeable  to  water,  light  and  spongy  and  of  a  dark  red 
color.  This  state  is  produced  by  catechuic  acid  and 
some  other  extractive  matters  which  are  found  in  the 
catechu. 

3.  When  we  macerate  tan  or  other  similar  substances, 
such  as  divi-divi  and  sumach,  with  water  for  tanning, 
those  substances  by  the  action  of  the  oxygen  of  the  air 
produce  gallic  acid,  which  is  a  solvent  of  gelatine,  and 
consequently  noxious  in  the  tanning,  at  the  same  time 
that  it  causes  an  expansion  in  the  pores  of  the  hide,  and 
as  it  does  not  help  in  the  combination  of  the  tannin 
with  the  gelatine,  the  leather  remains  spongy,  porous, 
and  of  an  inferior  quality. 


*  Sixth  year,  page  442. 


378 


TANNING. 


The  principal  object  of  M.  Turnbull  has  been  to  re¬ 
move  these  inconveniences  and  difficulties,  and  to  pro¬ 
duce  a  rapid  and  efficacious  combination  of  the  gelatine 
of  the  skin  with  the  tanning  matter. 

The  first  point  consists  in  removing  the  lime  contained 
in  the  skins,  or  to  use  other  means  of  raising  sugar  and 
saccharated  matters  contained  in  vegetable  substances, 
having  the  property  to  combine  with  lime  and  to  dis¬ 
solve  it.  It  is  the  same  with  pyroligneous  acid  or  wood 
vinegar,  consequently  to  extract  the  lime  contained  in 
skins  prepare  a  solution  consisting  of  14  pounds  of  saw¬ 
dust,  4  pounds  of  raw  sugar  and  300  quarts  of  water. 
It  can  also  be  composed  of  sawdust  alone  in  the  propor¬ 
tion  of  28  pounds  for  the  same  quantity  of  water.  The 
solutions  are  made  either  cold  or  warm,  but  always  used 
cold;  macerate  in  the  skins  for  two  or  three  days,  which 
is  sufficient  to  dissolve  all  the  lime. 

To  raise  the  skins  without  lime  Mr.  Turnbull  dips 
them  first  in  a  solution  of  sugar  or  any  saccharine 
matter;  second,  in  a  solution  of  common  salt.  By  the 
first  means  sugar  dilates  the  gelatine,  and  renders  the 
raising  easier.  In  the  second  the  salt  contracts  the  epi¬ 
dermis  without  acting  on  the  gelatine,  separates  it  from 
the  true  skin,  so  that  the  hair  can  be  taken  off  without 
producing  any  alteration  in  the  gelatinous  matter  of  the 
skin.  The  solution  of  sugar  is  thus  formed:  14  lbs.  of 
raw  sugar  or  molasses  for  112  galls,  of  water  kept  at  a 
temperature  between  50°  and  77°.  The  skins  are  left  in 
from  five  to  ten  days.  The  solution  of  salt  is  formed 
with  14  lbs.  of  salt  in  112  galls,  of  water  kept  at  a  tem¬ 
perature  between  68°  and  86°. 

Turnbull’s  process  to  separate  catechuic  acid  from 
the  other  principles  contained  in  catechu,  from  tannic 
acid,  and  to  avoid  the  formation  of  gallic  and  ellagic 
acid  when  gall,  oak  bark,  divi-divi,  etc.,  are  used,  is  the 
following: — 

Reduce  the  catechu  to  a  fine  powder,  treat  that  powder 
by  cold  water  until  no  more  is  dissolved.  Pour  the  cold 
solution  into  a  vat  or  cylinder  provided  with  a  metallic 
tissue  or  cotton  cloth.  The  catechuic  acid  insoluble  in 


Turnbull’s  process. 


379 


cold  water  stays  on  the  filter  and  the  solution  of  tannin 
is  freed  from  the  matters. 

To  prevent  the  formation  of  gallic  and  ellagic  acid  he 
reduces  the  material  into  powder  and  prevents  the  contact 
of  the  air  during  the  tanning,  as  we  shall  see  hereafter. 

The  skins  thus  prepared  are  well  washed  and  tanned 
by  two  different  processes.  First,  by  the  application  of 
a  certain  physical  force  different  from  capillary  attrac¬ 
tion  and  hydrostatic  pressure.  Second,  in  vats  com¬ 
municating  one  with  the  other,  as  we  shall  explain  here¬ 
after,  so  as  to  maintain  a  constant  agitation  and  circula¬ 
tion  in  the  tanning  matter,  until  the  skins  are  tanned. 

The  physical  force  that  Mr.  Turnbull  proposed  to 
apply  to  the  tanning  of  the  skins  is  that  one  which  pro¬ 
duces  the  endosmose  and  exosmose.  For  this  purpose  he 
takes  the  skins  to  form  bags  in  which  he  introduces  the 
tan  in  the  proportion  of  2  lbs.  for  every  pound  of  damp 
leather.  He  shuts  the  bags  in  which  he  keeps  a  small 
aperture  by  which  he  pours  in  cold  or  warm  water, 
then  hermetically  closes  the  hole.  These  bags  are  then 
introduced  in  closed  wooden  vats  filled  with  a  purified 
solution  of  catechu.  In  this  manner  during  the  opera¬ 
tion  the  solution  is  not  attacked  by  the  air,  and  the 
formation  of  gallic  acid  is  thus  avoided.  Thus,  to  in¬ 
crease  the  density  of  the  vats,  he  adds  14  lbs.  of  sugar 
for  every  112  galls,  of  liquor. 

The  two  liquors  thus  prepared  and  used,  the  effects  of 
endosmose  and  exosmose  are  produced,  and  tannic  acid 
passes  rapidly  through  the  skins  until  they  are  perfectly 
tanned.  Draw  the  bags  from  time  to  time,  and  when 
they  are  partly  emptied  by  the  filtration  they  are  filled 
again  with  water. 

During  the  tanning  it  is  necessary  to  keep  the  density 
of  the  liquor  of  the  vats  by  adding  to  it  sugar  from  time 
to  time.  Instead  of  catechu  you  can  use  Valonia  and 
even  tan  in  the  proportion  of  a  half  of  the  first.  For 
the  catechu  it  must  be  introduced  in  the  bags  only 
purified  and  in  solution  in  the  proportion  of  2  lbs.  of 
catechu  equal  to  8  lbs.  of  tan  for  10  lbs.  of  skins. 

You  can  dispose  a  series  of  vats,  closed  so  as  to  main- 


380 


TANNING. 


tain  a  constant  movement  and  circulation.  For  this 
purpose  fill  these  vats  with  a  liquor  composed  as  above, 
leaving  in  them  a  space  sufficient  to  introduce  the  skins 
one  on  another,  then  close  these  vats  so  as  to  exclude 
the  air,  and  finish  by  filling  with  the  liquor,  then  esta¬ 
blish  a  forcing  pump,  which  by  means  of  an  aspiration 
pipe  goes  to  the  bottom  of  each  vat.  Draw  the  tan¬ 
ning  liquor,  raise  it  and  pour  it  in  another  distribution 
pipe,  which  by  means  of  little  pipes  forces  it  to  the  upper 
part  of  the  vats. 

When  you  operate  on  catechu  to  separate  the  tannic 
acid  from  the  catechuic  acid,  and  other  useless  matters, 
the  deposit  which  forms  in  the  vat  is  at  least  five  per 
cent,  in  weight  of  the  catechu  put  in  dissolution.  This 
deposit  can  be  purified,  and  rendered  proper  for  tanning. 
Deposit  it  in  an  oven,  or  in  an  evaporating  vessel,  and 
heat  it  at  161°,  then  expose  to  the  air,  and  stir  it  until 
it  takes  the  color  of  the  powdered  catechu.  This  matter, 
dissolved  and  filtered,  contains  as  near  as  much  tannin 
as  the  catechu  dissolved  in  the  first  place. 

The  skins  from  which  the  lime  has  been  separated,  or 
those  treated  without  lime,  can  be  tanned  in  the  usual 
way  with  catechu  purified  as  above,  or  with  other  tan¬ 
ning  substances.  The  leather  produced  by  this  process 
is  heavier,  and  of  better  quality  than  by  the  old  method. 

Later,  Mr.  Turnbull  gives  the  following  details.* 

“  The  economy  obtained  by  my  process  is  immense, 
and  I  will  prove  it  in  a  few  words. 

“  Thus,  100  lbs.  of  hide  in  the  green  state  furnish 
only  from  45  to  50  lbs.  of  tanned  leather,  requiring  300 
lbs.  of  oak  bark,  and  the  operation  lasts  18  months. 
By  my  method,  14  days  are  sufficient.  For  the  same 
weight  of  skin,  I  use  only  100  lbs.  of  oak  bark,  and 
after  the  operation,  I  obtain  60  lbs.  of  leather ;  while  by 
the  old  method  the  tanner  can  prepare  only  one  skin,  I 
can  prepare  39. 

“The  tanning  of  calf-skin  requires  by  the  usual  method 


*  Comptes  Rendus.  Acad,  des  Sciences,  Janvier  12,  1846. 


sntder’s  process. 


381 


from  five  to  six  months ;  from  two  to  four  days  are  suffi¬ 
cient  by  my  process. 

“At  last,  if  the  tanner  will  use  only  the  first  part  of 
my  process,  that  is  the  saccharated  solution,  destined  to 
prevent  the  action  of  the  lime,  he  reduces  the  operation 
for  calf-skins  from  six  months  to  ten  days.” 


CHAPTER  XCIII. 

S.  SNYDER’S  PROCESS. 

Every  one  knows  how  important  it  is  to  saturate  the 
hides  with  tannin  as  quickly  as  possible  after  they  have 
been  prepared  to  be  put  into  the  tanning  vats,  but  till 
now  this  saturation  has  been  done  so  slowly  that  it  is 
often  the  cause  of  losses  difficult  to  avoid.  We  will 
describe  now  a  process  which  enables  us  to  attain  this 
object  quickly,  and  which  we  have  no  doubt  can  be  used 
in  practice. 

Mr.  Snyder  takes  the  hides  after  the  working  in  the 
river,  when  they  are  very  soft  and  flexible,  and  he  acu¬ 
punctures  them  on  the  entire  surface,  that  is,  he  perforates 
them  with  an  instrument  presenting  a  surface  armed  with 
fine  steel  needles.  A  man  can  prepare  from  30  to  40 
hides  daily,  but  the  operation  can  be  rendered  more 
economical  and  rapid  with  the  help  of  a  machine.  For 
some  kinds  of  leather  you  must  acupuncture  on  the  grain 
side,  while  in  some  others  on  the  flesh  side. 

Every  one  admits  that  a  hide  thus  treated  will  be 
tanned  much  quicker  than  one  which  is  not;  but  this 
idea  to  perforate  thus  an  article,  the  object  of  which  is 
to  be  water-proof,  seems  a  paradox.  But  its  author  re¬ 
marks  that  it  is  when  the  hide  is  in  its  greatest  state  of 
softness  that  the  operation  is  performed,  and  he  affirms 
by  experiment  that  in  this  state  the  skin  is  not  altered. 
As  a  proof  he  presented  some  skins,  perforated  and 
tanned,  in  which  the  puncture  was  not  perceived  above 
the  grain.  Indeed  the  soft  skin  contracts  by  the  desic¬ 
cation,  and  the  tannin  with  which  it  is  impregnated 


382 


TANNING. 


gives  it  back  its  thickness  and  its  primitive  firmness,  in 
obliterating  all  the  pores  and  perforations. 

A  better  leather  can  be  prepared  by  this  method  than 
by  the  other,  for  the  following  reasons : — 

1.  Because  it  accelerates  the  tanning  so  as  to  require 
a  more  frequent  renewal  of  the  liquor,  which  has  no 
time  to  become  acid ;  for  it  is  a  known  fact  that  a  tan 
liquor  becomes  acid  in  ten  days,  and  in  the  ordinary 
process  the  leather  is  left  sometimes  6  or  8  weeks  in  the 
same  liquor,  which  consequently  becomes  sour.  He  sur¬ 
mounts  this  difficulty  by  exposing  a  more  considerable 
surface  of  fibres  to  the  immediate  action  of  the  tannin, 
which  causes  a  quicker  combination,  requires  a  more 
frequent  renewal  of  the  liquor  than  by  passing  it  through 
a  bed  of  powder,  and  insures  its  being  fresh  and  sweet. 

2.  Because  by  bringing  the  tannin  into  immediate 
contact  with  the  interior  fibres  a  chemical  change  is  pro¬ 
duced  at  the  same  time  as  that  on  the  exterior  surfaces, 
which  need  not  be  over-tanned.  This  exterior  surface 
is  rendered  hard  and  brittle  as  usual,  by  continuing  the 
action  until  the  tannin  has  penetrated  inside. 

According  to  the  author  he  can  tan  in  half  the  time 
of  the  ordinary  process,  and  consequently  save  much 
cost  and  labor.  If  you  want  to  operate  quicker,  hy¬ 
drostatic  pressure  can  be  applied,  which  does  very  well 
with  the  acupuncture,  and  it  requires  less  pressure  than 
that  usually  employed,  which  often  weaken^  the  fibres 
of  the  skin. 


CHAPTER  XCIV. 

H.  HIBBARD’S  PROCESS. 

This  process  unites  in  a  high  degree  the  advantages 
of  economy,  time,  and  labor.  It  is  applicable  to  all  kinds 
of  skins,  and  produces  a  solid  and  durable  leather.  The 
process  is  described  by  its  author  as  consisting: — 
“First.  In  the  use  of  a  composition  of  lime,  wood, 
ashes,  and  salt,  the  object  of  which  is  to  remove  hair  and 
wool,  also  for  liming  instead  of  using  lime  alone.  We 


hibbard’s  process. 


383 


have  described  the  objections  to  the  use  of  lime  and 
ashes  separately,  but  when  combined  in  proper  propor¬ 
tions  the  salt  modifies  the  action  of  the  alkalies  and  pro¬ 
tects  the  skin  from  their  caustic  properties,  so  that  the 
process  of  unhairing  is  rendered  more  expeditious  and 
safe  than  by  the  old  process.  The  texture  of  the  skin 
is  uninjured  and  the  leather  is  much  stronger. 

“  Second.  In  the  use  of  a  composition  of  salt,  sulphuric 
acid,  and  sumach,  oak,  hemlock,  or  any  other  tanning 
material.  The  salt,  sulphuric  acid,  and  tannin  being 
mixed  together  in  water  in  certain  proportions,  a  portion 
of  the  salt  is  decomposed  by  the  acid  to  form  sulphate 
of  soda,  and  set  at  liberty  hydrochloric  acid,  which  is 
redissolved  by  water,  acts  on  the  skins,  opens  the  pores, 
and  prepares  them  for  the  tannin,  which  being  present 
in  the  mixture,  readily  unites  with  the  principles  of  the 
skin  and  forms  leather  more  expeditiously  than  by  the 
old  method. 


P reparation  of  the  Skins. 

“  Prepare  the  following  composition : — 

Quicklime  (freshly  slacked)  .  .  .  \  bushel. 

Wood  ashes  .  .  .  .  .  •  i  “ 

Salt . 3  pints. 

“  To  remove  the  hair  mix  the  above  composition  with 
water  sufficient  to  make  a  thick  paste,  apply  it  to  the 
flesh  side  of  the  hides,  fold  the  skins  and  keep  them  at 
a  temperature  of  summer  heat.  In  a  few  hours  they 
are  ready  to  pull. 

“  For  the  liming  process  I  use  the  same  composition, 
mixed  with  a  sufficiency  of  water  in  a  vat  to  immerse 
the  number  of  skins  proposed  to  be  limed.  One  bushel 
is  equivalent  to  one  bushel  of  lime  alone.  The  liming 
is  done  at  the  temperature  of  60°. 

Composition  for  Tanning. 

“  For  six  dozen  of  full  sized  sheep,  deer,  goat,  or  simi¬ 
lar  skins,  prepare  the  following  composition : — 


384 


TANNING. 


Salt  .  .  .  .  .  .  .18  lbs. 

Sulphuric  acid  .  .  .  .  .  2  “ 

Sumach  or  quercitron  bark  .  .  36  “ 

Hydrochloric  acid  ....  2  ounces. 

Dried  clover . 18  lbs. 

Water  . 125  galls. 


“  Exhaust  the  sumach  by  water,  add  the  salt,  enough 
to  insure  perfect  solution.  Add  then  the  acids  and  in¬ 
corporate  by  stirring.” 


CHAPTER  XCV. 

HEMLOCK  TANNING. 

The  hemlock  forests  of  New  York  and  Northern 
Pennsylvania  are  very  extensive,  and  the  readiness  and 
cheapness  with  which  the  bark  may  be  obtained  have 
brought  it  into  general  use,  in  those  States,  as  tanning 
material.  It  may  be  employed  alone  or  in  combination 
with  oak  bark. 

In  order  to  produce  heavy  weights  the  hides  should 
not  be  reduced  too  low  in  the  beam  house,  and  should 
be  tanned  quickly  with  strong,  good  liquors,  principally 
in  the  last  stages  of  the  operation.  Nothing  is  more 
injurious  to  green  hides  than  to  leave  them  too  long  in 
weak  ooze ;  they  become  too  much  reduced,  grow  soft, 
hat  and  flabby ;  lose  a  portion  of  their  gelatine,  and 
refuse  to  plump  up. 

The  soaking  and  sweating  are  made  in  the  ordinary 
manner,  and  the  following  table  shows  the  time  em¬ 
ployed  for  these  operations  at  different  temperatures: — 


400. 

500. 

600. 

700. 

Soaking. 

Days. 

Days. 

Days. 

Days. 

Buenos- Ayres  hides  . 

10  to  12 

8  to  12 

6  to  8 

3  to  6 

Carthagena  “  . 

8  to  12 

7  to  9 

5  to  7 

2  to  3 

Sweating. 

Buenos- Ayres  “  . 

15  to  20 

12  to  16 

8  to  12 

2  to  3 

Carthagena  “  . 

15  to  20 

10  to  15 

6  to  8 

2  to  3 

Soaked  hides  do  not 

require 

more  than  two-thirds  of 

the  time  to  soak,  but  rather  longer  to  sweat. 

After  these  operations  are  done,  pass  to  the  handling , 


HEMLOCK  TANNING. 


385 


which  is  performed  two  or  three  times  a  day  in  a  weak 
ooze  until  the  grain  is  colored.  New  liquors,  or  mix¬ 
tures  of  new  and  old  are  preferable  for  dry  hides,  old 
liquors  for  slaughtered.  They  are  then,  after  a  fortnight, 
laid  away  in  bark,  and  changed  once  in  two  or  four 
weeks  until  tanned.  Much  care  and  judgment  are 
necessary  in  proportioning  the  continually  increasing 
strength  of  the  liquors  to  the  requirements  of  the  lea¬ 
ther  in  the  different  stages  of  the  process.  The  liquors 
should  also  be  kept  as  cool  as  possible,  within  certain 
limits,  but  ought  never  to  exceed  a  temperature  of  80°. 
Too  high  a  heat,  with  a  liquor  too  strongly  charged  with 
the  tanning  principle,  is  injurious  to  the  life  aud  color 
of  the  leather.  If  too  strong  a  solution  is  injurious,  the 
use  of  a  too  weak  one  must  be  avoided.  Hides  treated 
with  liquors  below  the  proper  strength  become  relaxed 
in  their  texture  and  lose  a  portion  of  their  gelatine. 
The  leather  loses  in  weight,  and  is  much  more  porous. 
The  greatest  strength  of  liquor  used  for  handling  must 
mark  16°  by  the  barkometer ;  and  that  employed  in 
laying  away  must  mark  at  its  greatest  strength  from  30 
to  45°. 

After  the  leather  has  been  thoroughly  tanned  and 
rinsed,  or  scrubbed  by  a  brush  machine  or  broom,  it  will 
tend  very  much  to  improve  its  color  and  pliability  to 
stack  it  up  in  piles  and  allow  it  to  sweat  until  it  becomes 
a  little  slippery  from  a  kind  of  mucus  that  collects  upon 
its  surface.  A  little  oil  added  at  this  stage  of  the  pro¬ 
cess  has  been  found  very  useful. 

The  average  time  of  tanning  by  hemlock  amounts  to 
five  months  twenty-seven  days.  The  English  tanners 
employ  from  eight  to  ten  months. 

We  need  not  dwell  much  longer  on  this  process, 
which  is  the  same  as  with  oak  bark.  The  leather  it 
produces  is  good,  and  easily  recognized  by  its  red  color. 

To  tan  sole-leather  with  hemlock  takes  from  four  to 
six  months,  according  to  the  strength  of  the  liquor  and 
number  of  sides  in  the  vats ;  and  the  quicker  tanned 
the  better.  The  weight  of  the  hides  if  heavy  requires 
more  time  than  if  comparatively  light.  If  the  hides 
25 


386 


TANNING. 


are  fresh,  they  are  capable  of  being  properly  softened  ; 
and  if  so,  the  process  of  tanning  may  be  completed 
sooner  than  in  the  case  of  old  and  hard  hides  that  can¬ 
not  be  softened  so  easily.  If  the  hides  have  sufficient 
room  in  the  vats,  they  will  tan  much  faster.  As  the  tan¬ 
ning  advances  the  liquor  should  be  renewed  seasonably, 
and  its  strength  increased  in  a  ratio  proportionate  to 
each  stage  of  tanning. 

Process  of  Tanning  as  Performed  at  the  Shaker  Tan¬ 
nery  o  f  New  Lebanon ,  N.  Y. — We  are  indebted  to  M. 
Fred.  Sizer,  the  Shaker  tanner,  for  the  following  account 
of  the  process  of  tanning-  as  performed  in  that  village. 
All  those  who  are  acquainted  with  the  products  of  that 
society  will  know  the  value  of  this  process,  which  we, 
without  hesitation,  recommend  as  purely  practical.  We 
give  it  in  the  words  of  its  author: — 

“I  take  a  pack  of  calf-skins — say  one  hundred  dry 
skins — and  put  them  in  a  water  vat  to  soak;  after  they 
have  soaked  two  or  three  days,  I  take  them  out  and  mill 
them  (a  wheel  is  best  for  milling  hides).  I  then  beam 
them  on  the  flesh  side,  removing  all  the  lean  meat  and 
grease  from  the  skin,  stretching  them  out  well  with  the 
beaming  knife,  and  put  them  into  a  vat  of  clean  water 
until  they  are  soft  enough  to  go  in  the  lime.  They  must 
be  as  soft  as  they  were  when  they  came  off  the  animal, 
or  as  near  that  as  you  can  get  them.  If  the  hides  are 
not  soft  before  going  in  the  lime,  they  never  can  be, 
and  the  leather  will  always  be  hard. 

“Fresh  hides  that  come  directly  from  the  butcher  are 
put  in  the  water  a  day  or  two;  change  the  water  once ; 
beam  on  the  flesh  side  to  get  the  meat  and  grease  off, 
then  they  are  ready  for  the  lime. 

“  I  make  my  lime  in  a  vat  8  feet  long,  4  wide,  and  4 
dee]).  One  bushel  of  slaked  lime  and  2  gallons  soft  soap, 
put  in  the  vat  two-thirds  full  of  water,  will  make  a  lime 
sufficient  for  100  calf-skins,  or  50  sides  of  upper  leather. 
The  hides  should  be  hauled  out  every  other  day,  while 
in  the  lime,  to  air  and  change  their  position;  then  stir 
the  lime  well  before  they  are  put  back. 

“  The  lime  needs  strengthening  every  time  a  new 


i 


HEMLOCK  TANNING. 


387 


pack  is  put  in,  by  adding  say  half  bushel  lime  and  two 
or  three  quarts  soap.  I  lime  my  calf-skins  and  upper 
leather  hides  until  the  hair  comes  off  easily  (but  sole 
leather  should  be  limed  as  little  as  possible  and  get  the 
hair  off);  then  unhair  them,  wash  them  out  in  the  mill, 
beam  them  on  the  flesh  side,  trim  off  the  pates  and 
shanks,  and  put  them  in  the  bate. 

“I  put  5  or  6  bushels  hen  dung  into  a  vat  of  the  same 
dimensions  of  that  used  for  the  lime,  and  fill  two-thirds 
full  of  water,  and  let  it  stand  two  or  three  days  to  fer¬ 
ment.  I  let  my  skins  remain  in  the  bate  two  or  three 
days  in  warm  weather,  and  longer  in  cold;  haul  them 
two  or  three  times  while  in  the  bate,  and  work  them 
twice  on  the  grain  with  a  common  worker  on  the  tan¬ 
ners’ beam;  mill  them  before  working  the  last  time; 
then  beam  them,  and  they  are  ready  for  the  tan  vats. 

“I  make  a  liquor  of  moderate  strength  to  handle  them 
in,  put  them  in  this  liquor,  and  stir  them  with  pole  a 
while;  then  I  handle  them  up  smooth  on  a  box  or  rack 
three  or  four  times  in  the  course  of  the  day;  let  them 
remain  in  this  until  the  next  morning,  then  change  the 
liquor,  giving  them  about  the  same  strength  they  had 
the  first  time;  handle  them  two  or  three  times  a  day  in 
this  liquor,  and  when  the  liquor  is  exhausted  change 
again  and  handle  less  as  the  skins  get  colored  and  the 
grain  set.  I  make  my  liquors  of  hemlock  bark,  ground 
and  put  in  leeches,  and  pump  in  exhausted  liquor.  The 
first  strength  of  my  leeches  I  draw  off  into  my  sole  leather 
vats;  I  draw  off  my  leeches  two  or  three  times  before 
taking  it  for  my  upper  leather  and  calf-skins,  and  these 
I  keep  in  mild,  sweet  liquors  through  the  whole  tanning 
process. 

“I  handle  my  hides  and  calf-skins  through  until 
tanned,  changing  the  liquors  as  they  get  exhausted. 
After  they  get  well  along,  I  handle  three  times  a  week. 
They  will  do  to  lay  longer,  but  will  tan  faster  to  handle 
often. 

“  When  my  calf-skins  have  been  in  the  tan  two  or 
three  weeks,  I  shave  down  the  necks ;  and  after  my 


388 


TANNING. 


upper  leather  has  been  in  four  or  five  weeks,  I  shave  it 
down  to  a  proper  thickness. 

“In  my  experience  in  tanning,  which  has  extended 
through  forty-two  years,  and  I  have  used  both  hemlock 
and  oak  bark,  I  find  that  mild,  sweet  liquors  are  far  the 
best  for  tanning  all  kinds  of  upper  leather.  The  hide 
in  the  raw  state  is  tougher  than  when  tanned,  and  that 
toughness  ought  to  be  preserved  as  much  as  possible  and 
make  good  pliable  leather,  and  the  slow  process  of  tan¬ 
ning  with  mild  liquors  will  do  it.  Strong  liquors  have 
a  tendency  to  make  the  leather  hard  and  liable  to  crack. 

“The  hides  for  upper  leather  should  not  be  tanned 
any  more  than  thoroughly  through;  if  tanned  longer 
than  this,  it  has  the  same  effect  upon  them  as  strong 
liquor.  But  the  longer  sole  leather  is  tanned  the  better. 

“When  I  think  my  leather  is  nearly  struck  through 
I  try  it  by  cutting  into  the  thickest  edge,  and  when 
tanned  through  take  it  up  and  scour  it  out  in  the  wheel 
to  cleanse  it  from  the  tan  and  soften  the  grain;  then 
take  them  to  the  currying  shop,  and  the  calf-skins  I 
skive  and  upper  smooth  down  with  the  currying  knife; 
then  put  them  in  a  tub  of  water  and  scour  them  on  the 
table  with  a  brush,  stone,  and  slicker;  dry  them  a  little 
to  temper  them,  and  then  put  them  on  the  table  and  set 
them  on  the  grain  side  to  work  the  grain  out  smooth. 
After  that  apply  some  thin  stuffing  made  of  oil  and 
tallow ;  then  turn  them  over,  the  flesh  side  up,  and  set 
them  out  with  an  iron  slicker;  then  apply  the  stuffing 
more  plentifully,  made  thicker  with  more  tallow;  then 
hang  them  on  sticks  and  dry  them,  and  then  pack  them 
down  in  a  pile  and  let  them  stay  two  weeks.  I  then 
take  them  and  rub  off  what  stuffing  does  not  strike  in, 
and  whiten  them  with  a  currying  knife  or  slicker. 

“  I  commonly  whiten  my  calf-skins  and  kips  with  a 
slicker,  and  finish  in  the  French  style. 

“  Since  the  French  degras  has  come  into  use  I  have 
used  it  for  calf-skins  and  kips.  I  have  also,  for  some 
time,  used  tansy  in  my  liquors.  There  is  an  acid  in  tan 
that  injures  the  leather  which  tansy  neutralizes,  and 
keeps  the  liquor  sweet.” 


halvorson’s  process. 


389 


CHAPTER  XCYI. 

HALVORSON’S  PROCESS  FOR  RENDERING  HIDES  HARD 
AND  TRANSPARENT. 

This  method,  patented  by  H.  ITalvorson,  is  thus 
described: — 

“  I  take  the  raw  hide  and  submit  it  to  the  sweating 
operation  sufficiently  to  remove  the  hair,  or  I  immerse 
the  hide  in  a  solution  of  lime  or  alkali  proper  to  remove 
the  hair.  I  then  submit  it  to  the  action  of  a  boiling 
bath  of  any  powerful  astringent  and  alkaline,  orany  other 
substance  sufficient  to  remove  the  fatty  matter  and  make 
it  thicker. 

“  So  far  as  my  experience  goes  I  find  sulphuric  acid, 
salts  of  tartar,  and  alum,  dissolved  in  water,  to  answer 
a  good  purpose.  I  keep  the  hide  in  the  boiling  solu¬ 
tion,  stirring  frequently,  and  handling  the  hides  while 
under  the  influence  of  the  bath,  in  order  to  cause  the 
liquid  to  penetrate  it. 

“  After  having  fulled  it  to  the  desired  thickness  I 
rinse  it  in  warm  and  clear  water  and  dry  it.  The  hide 
is  opaque,  and  is  very  easily  affected  by  the  atmospheric 
changes.  In  order  to  render  it  semi-transparent  and 
capable  of  resisting  the  influence  of  atmospheric  changes 
I  immerse  it  in  a  vessel  full  of  boiling  drying  oil,  and 
keep  it  in  until  a  white  or  yellowish  scale  begins  to  form 
on  its  surface,  then  I  remove  the  hide  from  the  fire. 
While  hot  it  can  be  pressed  or  moulded  into  various 
shapes.  When  cold  it  is  converted  into  a  substance 
resembling  horn  or  tortoise  shell,  and  may  be  worked 
like  them  or  ivory. 

“  If  the  hide  be  designed  for  embossed  works,  it  is 
advisable  to  remove  it  from  the  oil  as  soon  as  it  acquires 
the  desired  transparency  and  softness. 

“  After  being  thus  prepared  it  can  be  moulded.  During 
the  last  portions  of  the  process  the  material  may  be 
stained  by  adding  to  it  any  material  proper  to  produce 
an/  desired  color. 


390 


TANNING. 


“Where  it  may  not  be  required  to  thicken  a  hide  to 
its  greatest  extent  of  capacity  the  use  of  an  astringent 
solution  may  be  dispensed  with,  it  being  only  necessary 
in  such  cases  to  employ  the  alkaline  solution,  and  after¬ 
wards  expose  the  skin  to  the  action  of  boiling  as  above 
described.” 


CHAPTER  XCYII. 


TAWING. 

This  process  is  applicable  to  the  manufacture  of  soft 
leather  for  gloves  and  furriers’  uses,  as  skins  may  be 
subjected  to  its  action  even  in  their  hair  state.  It  is 
sometimes  called  alumed  leather ,  because  a  salt  of  alum¬ 
ina  is  the  basis  of  the  process.  The  skins  usually  sub¬ 
mitted  to  this  treatment  are  sheep,  lamb,  kid,  and  other 
light  skins. 

Kid  Leather. — The  first  operation  is  to  soak  the  skins 
well  in  running  water  and  to  break  them  upon  the  beam 
by  working  on  the  flesh  side  with  the  back  of  the  flesh¬ 
ing  knife.  Then  they  must  be  immediately  dried  to 
prevent  putrefaction,  which  will  render  them  spotted  and 
tender.  Dry  skins  require  a  soaking  of  one  or  two 
days. 

Then  rub  the  flesh  side  with  a  cold  milk  of  lime, 
place  them  back  to  back  in  pairs  with  the  back  out¬ 
wards,  stack  them  in  piles,  and  leave  them  several 
days  until  the  hair  gives  readily.  Rinse  them  in  running 
water,  to  remove  the  lime,  and  fleece  them ;  this  opera¬ 
tion  consists  in  plucking  out  the  hair  with  spring  tweez¬ 
ers,  and  smoothing  by  rubbing  with  a  whetstone  or 
rolling  pin.  Cleanse,  and  soak  again  in  the  lime  vat, 
whence,  after  being  removed,  they  are  transferred  to  an 
old  or  weaker  vat,  and  there  remain  for  a  fortnight  or 
more,  being  careful  to  take  them  out  and  drain  them 
frequently.  They  are  now  ready  for  the  brawling.  For 
this  purpose  they  undergo  a  steeping  for  10  or  15  days 
in  a  fermenting  mixture,  or  drench  of  40  galls,  of  bran 
and  20  galls,  of  water.  As  soon  as  the  skins  sink  in 


TAWING. 


391 


water  they  are  sufficiently  raised;  this  operation  re¬ 
quires  two  clays  in  summer  and  four  days  in  winter,  and 
great  care  is  necessary  to  observe  when  they  reach  that 
stage,  which  may  be  attained  earlier  by  frequently 
turning  the  skins. 

When  taken  from  this  liquor  they  are  put  in  the  white 
hath ,  composed,  for  100  skins,  of  a  boiling  solution  of  10 
to  12  lbs.  of  alum  in  12  galls,  of  water,  to  which  you 
add,  in  summer,  2h  lbs.  of  common  salt,  and  in  winter 
3  lbs.  Divide  the  skins  into  four  equal  parcels,  and  pass 
each  parcel  separately  and  successively  in  this  bath,  and 
then  immerse  the  whole  together  for  ten  minutes. 

Make  a  paste  by  gradually  adding,  during  a  constant 
stirring,  firstly,  15  lbs.  of  wheat  flour  to  the  alum  bath 
gently  heated,  and  subsequently  the  yelks  of  fifty  eggs, 
and  then  incorporating  the  whole  thoroughly.  The 
skins,  after  being  passed  in  this  paste  singly,  are  trans¬ 
ferred  to  it  in  bulk  and  left  for  a  day. 

This  paste  has  an  emulsive  action,  softens  and  whitens 
the  skins,  counteracts  the  hardening  influence  of  after 
exposure  to  the  air,  and  tendency  to  brittleness. 

After  this  operation  stretch  the  skins  upon  poles  in  a 
drying  loft  and  there  leave  for  a  week  or  more,  as  may 
be  necessary.  They  are  then  ready  to  be  worked  upon 
the  softening  iron  to  stretch  them,  reduce  unevenness,  and 
develop  whiteness.  For  this  purpose  they  are  soaked 
in  water  for  5  or  6  minutes,  and  then  spread  and  soft¬ 
ened  by  the  process  of  staking. 

Next  they  are  stretched  on  hooks,  dried,  and  worked 
on  the  stretching  iron,  but  some  tanners,  after  the  skins 
come  from  the  smoothing  iron,  spread  them  upon  the 
beam  with  a  clean  undressed  skin  beneath,  and  work 
them  with  the  fleshing  knife. 

Sometimes  the  prepared  skin  is  polished  by  being 
rubbed  with  pumice.  The  lustre  and  finishing  stroke 
are  given  with  a  smooth  flat-iron  carefully  heated. 

In  some  places  the  process  is  slightly  modified.  For 
example,  by  the  use  of  a  large  barrel  churn,  or  round¬ 
about,  which  receives  both  the  skin  and  the  alum  bath. 
Kapid  rotation  of  the  apparatus  promotes  constant  con- 


392 


TANNING. 


tact  of  the  skins  and  tanning  material,  and  accelerates 
the  operation.  The  tanned  skins,  after  coming  from  the 
paste,  and  being  washed  and  dried,  are  subjected  to  the 
staking,  which  consists  in  the  use  of  a  semicircular  iron 
plate,  fixed  perpendicularly,  with  its  round  edge  upper¬ 
most,  to  the  top  of  a  wooden  stake  about  thirty  inches 
high.  The  workman,  holding  the  skin  distended  by 
both  hands,  draws  it  forcibly,  and  in  every  direction, 

Fig.  116. 


over  the  blunt  edge  of  this  tool,  and  thus  imparts  soft¬ 
ness  and  smoothness  to  it. 

Tawed  leather  is  raw  skin  combined  with  chloride  of 
aluminum.  The  alum  is  decomposed.  Its  aluminum 
combines  with  the  chlorine  of  the  chloride  of  sodium 
(salt),  and  the  sulphuric  acid  of  the  alum  forms  a  double 
sulphate  of  potash  and  soda,  as  represented  in  the  fol¬ 
lowing  reaction: — 

K0,S03,  A1303  3(S03)  +  8C1  Na  =  KO  S03  +  BNaO  S03  +  C13A12 

Chloride  of  Sulphate  of  Sulphate  of  Chloride  of 
Alum.  Sodium.  Potash.  Soda.  Aluminum. 

Imitation  Kid. — -Imitation  kid  is  made  from  lamb¬ 
skins.  Lime  is  not  used  in  order  to  remove  the  wool 
without  injury.  Steep  the  skins  in  water,  and  break 
them  on  the  flesh  side ;  suspend  them  in  a  subterranean 


METHOD  OF  TANNING  SMALL  LAMB-SKINS. 


393 


vault  twelve  feet  square,  protected  as  much  as  possible 
from  atmospheric  changes,  so  that  the  temperature  stays 
the  same  all  the  year  round.  An  incipient  putrefaction 
is  promoted,  the  roots  of  the  wool  are  loosened,  and  it  is 
readily  plucked  from  the  pelt ;  and  when  this  state  is 
reached,  which  takes  from  five  to  seven  days,  the  skins 
are  removed,  to  avoid  injury. 

The  skins  are  then  slimed ;  that  is,  are  scraped  on  the 
flesh  side,  stripped  of  wool,  and  steeped  for  a  week  in 
lime  water,  fleshed  on  the  beam,  drenched  for  some  days 
in  a  fermenting  bran-bath,  and  treated  with  alum  and 
salt  in  the  same  manner  as  true  kid.  Dyeing,  softening, 
and  polishing  complete  the  preparation  of  the  leather. 


CHAPTER  XCVIII. 

THE  BEST  METHOD  OF  TANNING  SMALL  LAMB-SKINS, 
CALLED  CHAMOIS,  AND  ESPECIALLY  WHITE  PELTRY 
FOR  FURRIERS. 

M.  A.  Bruggemann  describes  a  process,  the  principal 
result  of  which  is,  that  the  skins  retain  their  fur,  and 
that  they  remain  dazzlingly  white ;  further,  that  they 
become  strong  and  exceedingly  soft,  which  is  best  attain¬ 
able  in  the  following  manner : — 

The  skins  should  be  allowed  to  soak  about  eighteen 
hours  in  water,  but  not  longer,  or  the  fur  will  become 
loosened  and  the  skin  be  rendered  useless  as  peltry. 
Then  they  should  be  taken  out  of  the  water,  and  rinsed 
in  running  water.  After  the  water  has  been  drained 
off,  or  pressed  out,  the  skins  should  be  laid  separately, 
with  the  fur  sides  uppermost,  on  a  table  or  suitable 
board,  and  then  carded,  one  after  another,  with  the 
coarsest  description  of  wool  comb,  especial  attention 
being  paid  to  the  dirtiest  spots,  and  great  care  taken  that 
the  fur  may  not  be  injured.  The  dirtiest  spots  should 
be  rubbed  with  soap,  and,  that  it  may  thoroughly  take 
effect,  the  soaked  skins  should  be  allowed  to  remain  un¬ 
touched  one  or  two  hours.  When  there  are  large  lots 
to  be  dressed  together,  the  work  goes  on  without  inter- 


394 


TANNING. 


ruption  on  this  account,  the  skins  first  soaped  being  the 
first  ready  for  the  next  state  of  the  process.  After  the 
soaping,  and  after  it  has  been  allowed  the  necessary 
time  to  work  in,  the  skins  require  to  be  once  more  carded, 
especially  upon  the  soaped  places.  Then  will  be  seen 
which  portion  of  the  pelt  stands  in  need  of  a  more 
further  soaping ;  this  should  be  done  at  once,  and  the 
skins  allowed  to  lie  a  short  time  longer,  that  the  soap  may 
take  effect;  then  they  should  be  carded  and  washed  clean. 

Those  skins  found  to  be  quite  clean  should  be  washed 
or  rinsed  in  running  water,  which  ends  this  part  of  the 
process.  The  washing  out  of  the  pelts,  like  all  the  pre¬ 
ceding  operations,  requires  great  care  in  order  to  make 
them  of  uniform  cleanliness.  The  skin  should  be  held 
by  one  of  the  hind  legs,  that  the  other  leg  and  the  entire 
hinder  part  of  the  skin  may  be  turned  in  washing  evenly 
right  and  left,  so  that  the  other  portions  of  the  skin  may 
continue  in  level  motion  on  the  water.  If  this  particu¬ 
lar,  however  insignificant  it  may  appear,  be  not  attended 
to,  clean  pelts  cannot  be  obtained  without  much  loss  of 
time.  After  the  skins  are  cleaned  on  the  fur  side^  and 
the  water  drained  off  or  squeezed  out  of  them  as  much 
as  possible,  the  flesh  or  fibrous  part  of  the  skin  is  re¬ 
moved  by  drawing  it  over  a  stationary  iron  instrument 
contrived  for  the  purpose.  This  fleshing  operation  is  also 
intended  to  render  the  skin  pliant,  and  is  of  importance 
to  its  ultimate  softness.  After  fleshing,  the  skins  should 
be  laid  singly  on  a  board,  with  the  fleshy  side  uppermost, 
and  carefully  examined,  heads,  legs,  tails,  etc.  Then  take 
barley  groats,  or,  in  the  absence  of  this,  a  mixture  made 
of  3  parts  wheat  bran  and  2  parts  rye  flour,  which  will 
answer  the  same  purpose,  and  strew  a  layer  of  barley 
groats  or  the  other  mixture  over  each  skin,  covering  the 
surface  uniformly.  Then  roll  each  skin  together,  with 
the  wool  or  fur  side,  of  course,  outward,  with  the  legs, 
head,  and  edges  well  tucked  in,  and  pack  them  thus 
rolled  one  by  one  in  a  water-tight  vat.  When  the  vat 
is  tolerably  full,  or  the  stock  of  skins  exhausted,  pour 
salt  water,  that  will  bear  an  egg,  upon  the  skins,  and 
sufficient  to  cover  them  entirely.  They  should  be  left 


METHOD  OF  COLORING  WHITE  TAWED  LIQUOR.  395 

to  remain  there  about  twenty-four  hours.  It  must  be 
noted  that  the  vat  containing  the  skins  should  stand  in 
a  cellar,  or  in  some  other  cool  place,  where  it  can  be 
protected  against  frost.  After  the  specified  time  the 
skins  should  be  carefully  unrolled,  so  that  the  bestrewn 
parts  be  as  little  disarranged  as  possible;  then  lay  them 
with  the  fur  side  inwards,  by  twos  flat  together,  the  head 
of  one  being  upon  the  tail  of  the  other,  and  pack  them 
thus  flatly  in  another  vat.  Care  must  be  taken  not  to 
press  out  the.  moisture  remaining  in  the  skins,  as  their 
peculiar  nourishment  or  fermentation  would  thus  be  re¬ 
moved.  During  fourteen  days,  or  ten  will  be  sufficient 
at  a  high  temperature,  the  skins  must  be  daily  re-packed 
and  changed  to  another  vat,  so  that  all  their  parts  may 
absorb  the  liquor  uniformly.  If  this  is  not  carefully 
attended  to  daily,  the  skins  will  certainly  be  speckled, 
and  possibly  entirely  ruined.  After  the  time  mentioned, 
the  skins  should  be  taken  out  of  the  vat,  drained,  and 
the  moisture  got  rid  of  by  pressing  or  squeezing ;  then 
they  are  dried,  and  the  dressing  process  begins. 

CHAPTER  XCIX. 

NEW  METHOD  OF  COLORING  WHITE  TAWED  LEATHER. 

Pelts,  to  be  well  colored,  should  be  made  perfectly 
smooth  on  the  flesh  side  before  being  cleaned ;  this  is 
accomplished  by  reducing  the  thickness  of  the  skin  on 
that  side  by  means  of  the  flesher  and  then  making  it 
perfectly  even.  In  order  to  facilitate  this  operation,  and 
that  the  flesher  may  take  better  hold  of  the  portion 
which  it  is  desired  to  remove,  the  side  of  the  pelt  ope¬ 
rated  upon  ought  to  be  well  rubbed  in  with,  thin  chalk 
paste.  After  the  skin  has  been  properly  smoothed  it  is 
cleaned,  wrung  out,  dried,  and  stretched  out.  The  next 
operation  is  to  place  it  on  a  tin  or  zinc  table,  with  the 
flesh  side  outward,  to  stretch  it  tightly,  and  then  to  apply 
to  its  surface  the  desired  coloring  matter  by  means  of  a 
soft  brush  with  long  hair.  After  this,  and  while  the 
pelt  is  still  damp,  it  should  be  well  rubbed  in  with 


396 


TANNING. 


pumice  stone,  being  for  that  purpose  stretched  out  on  a 
frame.  The  workman  performing  this  part  of  the  ope¬ 
ration  holds  with  his  left  hand  the  frame,  on  which  the 
skin  is  extended,  and  rubs  it  downwards  with  the  pumice 
stone  which  he  presses  as  hard  as  he  can.  The  skin 
should  be  thus  pumiced  from  the  tail  to  the  head,  then 
again  from  the  head  to  the  tail,  and  then  from  flank  to 
flank,  the  latter  if  the  condition  of  the  skin  requires  it. 
After  pumicing  the  pelts  are  dried  on  wooden  platforms 
or  scaffoldings,  provided  with  hooks,  in  a  room  where 
they  can  be  so  hung  as  not  to  touch  each  other.  The 
dried  skins  are  again  placed  on  the  table  as  before, 
receive  the  second  coating  of  color,  and  are  again  carried 
to  the  scaffolding  to  dry.  This  operation  is  repeated  a 
third  time,  and  if  the  color  answer  the  expectation  the 
labor  is  completed;  if  it  should  not  prove  sufficiently 
dark,  a  fourth  coating  will  bring  it  to  the  desired  shade, 
but  this  is  seldom  required,  except  for  skins  intended 
for  the  best  description  of  gloves. 

This  method  is  called  the  Parisian  method ;  it  differs 
from  the  one  called  the  Grenoble  method.  In  the  former 
the  skins  are  colored  three  or  four  times,  while  in  the 
latter  the  operation  is  performed  but  once.  The  disad¬ 
vantage  of  the  Parisian  metlcod  is  that  the  repeated  re¬ 
moval  of  the  skin  from  the  table  to  the  scaffolding  and 
back  again  subjects  them  to  the  danger  of  being  soiled; 
this,  however,  can  be  avoided  by  careful  handling,  and 
the  disadvantage  is  counterbalanced  not  only  by  the 
color  being  more  uniform  and  true,  but  by  the  supple¬ 
ness  which  the  skin  acquires  by  this  operation. 

CHAPTER  C. 

QUICK  TANNING. 

Tanners  and  leather  dealers  are  often  charged  with 
being  opposed  to  innovations,  and  slow  in  adopting  or 
introducing  improvements.  This,  to  a  certain  extent, 
may  be  true,  but  we  can  hardly  believe  that  tanners,  as 
a  class,  are  more  indifferent  than  others  to  their  own 


QUICK  TANNING. 


397 


interests.  It  is  undoubtedly  true  that  the  various  steps 
in  the  process  of  tanning  have  been,  and  still  are,  to  a 
large  portion  of  American  tanners,  merely  mechanical. 
They  do  not  understand  the  principles,  and  know  results 
only  as  a  matter  of  experience.  This  want  of  knowledge 
has  left  a  large  field  for  fraud  and  imposition,  which  has 
not  been  unimproved.  There  is  hardly  a  tanner  in  the 
country,  who  has  not,  some  time  or  other,  paid  dearly 
for  some  alleged  important  information,  new  invention, 
patent  process,  etc.,  which  have  proved  worthless,  and 
smarting  under  the  failure  of  some  impostor’s  theory,  is 
it  any  wonder  that  the  tanners  became  jealous  and 
backward  in  adopting  new  processes.  We  believe,  if  it 
be  fully  proved  to  the  tanners  that  an  invention  is  an 
actual  improvement,  that  there  is  no  class  of  men  more 
willing  to  receive,  use,  and  pay  for,  such  inventions. 
They  are  a  class  more  sinned  against  than  sinning. 

Many  tanners  maintain  that  there  is  no  advantage 
whatever  in  keeping  leather  in  process  after  the  gelatine 
and  tannin  have  united.  There  is  much  diversity  of 
opinion  upon  the  length  of  time  necessary  or  advan¬ 
tageous,  to  keep  leather  in  the  tanning  liquor,  but  it 
doubtless  depends  very  much  upon  the  preparation  of 
the  hide.  Tanners  generally  do  not  pay  proper  attention 
to  the  early  steps — those  of  unhairing  and  raising.  Is 
there  any  necessity  that  time  be  given  after  the  tannin 
and  gelatine  have  united,  for  leather  to  consolidate  and 
grow?  Is  there  any  gain  in  weight,  if  even  made  more 
durable  by  such  delay?  What  length  of  time  is  it  neces¬ 
sary  to  let  hides  tan  which  are  limed  or  sweated  in  the 
common  method  ?  These  are  questions  often  asked,  and 
on  which  the  views  of  practical  men  are  desired. 

The  fact  is,  that  when  the  tannin  and  gelatine  are 
completely  united,  the  process  of  the  formation  of  leather 
is  exhausted.  But  in  the  ordinary  manufacture  it  is 
never  the  case  that  the  hide  has  received  all  the  tannin 
of  which  it  is  capable,  and  therefore  an  extension  of  time 
is  followed  by  an  increase  of  weight.  If  all  the  gelatine 
of  the  hide  could  be  exposed  at  the  same  moment  to  the 
action  of  the  tannin,  the  process  would  be  instantaneous, 


398 


TANNING. 


and  this  is  what  the  patented  processes  profess  to  facili¬ 
tate.  There  is  no  doubt  that  improvements  in  this 
direction  are  feasible,  and  that  a  considerable  time  is 
now  actually  gained  over  the  old  periods  of  manufacture 
without  an  injury  to  the  leather.  But  no  improvement 
has  yet  so  facilitated  the  quick  production  of  leather, 
that  a  material  gain  in  weight  may  not  be  secured  by  a 
protracted  stay  in  the  vats,  while  attempts  of  this  kind 
by  the  use  of  deleterious  substances  have  often  resulted 
in  rotting  the  fibre  of  the  hide. 

Has  there  ever  been  any  leather  tanned  in  two,  three, 
or  six  months,  by  any  patented  process,  which  has 
claimed  to  be  equal  to  the  English  band  leather  ;  and 
what  gives  the  great  superiority  to  this  class  of  leather 
if  not  the  length  of  time  it  is  in  tali'?  It  is  well  known 
that  the  oak  tanners  of  Pennsylvania  and  Maryland  are 
about  twice  as  long  in  tanning  leather  as  the  hemlock 
tanners.  May  it  not  be  this  length  of  time  in  tanning 
which  gives  the  general  superiority  to  oak  leather'?  It 
is  a  general  complaint  that  leather  tanned  by  quick 
processes  is  wanting  in  solidity  and  strength.  It  is 
porous,  easily  filled  with  water,  and  wanting  in  durable 
qualities.  A  few  years  since  a  tanner  in  Pennsylvania 
had  several  hundred  sides  of  leather  in  vats  tanned  the 
usual  time.  A  part  of  this  leather  had  been  dried  out 
and  sent  to  market,  when  an  event  occurred  that  entirely 
stopped  the  working  of  the  yard  for  six  months,  and  the 
residue  of  the  leather  remained  undisturbed  in  the  vats. 
This  was  finally  sent  to  market,  and  on  comparison  with 
the  stock  sent  six  months  earlier,  was  found  to  be  a 
much  superior  article,  besides  having  gained  from  6  to  8 
per  cent,  in  weight.  We  do  not  mention  this  as  an 
example  for  imitation,  but  simply  to  show  that  tanners, 
under  the  common  system,  frequently  hurry  out  their 
leather  before  they  realize  the  full  gain. 

We  give  below  a  few  of  the  quick  tanning  processes. 
We  could  have  given  more,  but  in  reality  they  are  all 
much  the  same ;  they  vary  only  in  proportions. 

M.  D.  Kennedy's  Process. — In  this  process  the  author 
uses  the  divi-divi,  catechu,  oak.  He  combines  the  tan- 


QUICK  TANNING. 


399 


nin  with  the  sulphates  of  soda,  magnesia,  alumina,  car¬ 
bonate  and  borate  of  soda.  The  liquor  of  the  vats  is 


prepared  with — 

Tanning  material  ....  30  lbs. 

Sulphate  of  soda  ....  8  “ 

Sulphate  of  magnesia  .  .  .  4  “ 

Alum . 1  “ 

Carbonate  of  soda  ....  2  “ 

Borate, of  soda  .....  1  “ 

Ammonia.  .....  1  “ 

I.  L.  Wells'  Process. — The  composition  used  by  the 
author  is  the  following: — 

Soft  water  .  .  .  .  .  128  galls. 

Catechu  .....  100  lbs. 

American  sumach  .  .  .  150  “ 


J.  Cochrans  Process. — The  hair  is  removed  from  the 
hides  by  any  of  the  known  processes,  after  which  they 
are  handled  from  two  to  four  days  in  the  following  com¬ 
pound  or  solution: — 


Water 

8  gallons. 

Terra  japonica  . 

8  lbs. 

Salt  . 

16  “ 

Elder  extract 

8  ounces. 

Saltpetre  . 

2  lbs. 

Alum 

1  lb. 

Aloes 

1  “ 

Opium 

• 

1  ounce. 

This  composition  is  too  costly  to  employ  in  the  usual 
practice,  and  we  doubt  its  efficacy. 

W.  E.  Webster's  Process. — The  hair  is  removed  by 
the  usual  process,  and  the  hides  are  passed  through  the 
bate,  and  then  are  saturated  by  passing  them  in  the 
following  solution: — 

Water.  .....  100  galls. 

Hypochloride  of  lime  ...  3  lbs. 

After  the  perfect  saturation,  they  are  passed  in  a 
combined  solution  of  tanning  material  and  hypochloride 
of  lime.  This  bath  is  thus  formed  : — 


Water . 100  galls. 

Hypochloride  of  lime  ...  3  lbs. 

Catechu  .....  30  “ 

Alum  .  .  .  .  .  .  6  “ 

Salt .  3  “ 


400 


TANNING. 


The  originality  of  this  process  consists  in  the  use  of 
bleaching  powder  (hypochloride  of  lime),  in  combination 
with  the  other  substances,  or  with  any  material  used  in 
the  process  of  tanning ;  but  we  believe  that  the  use  of 
the  bleaching  powder  is  more  injurious  to  the  hide  than 
beneficial,  and  we  will  not  advise  tanners  to  employ  such 
a  powerful  agent. 

Bunting's  Process. — The  following  are  the  proportions 
used  in  this  composition : — 


Boiling  soft  water  1  galls. 

Dry  elder  leaves  and  bark  .  .  4  oz. 

Terra  japonica  ....  15  lbs. 

Powdered  nutgalls  .  .  .  .  6  oz. 


Stir  thoroughly  until  completely  macerated,  add  then 
8  galls,  of  water,  1  lb.  of  potatoe  starch,  and  1  lb.  of 
salt ;  the  whole  is  stirred  when  it  is  ready  to  receive 
the  skins,  after  having  added  4  ounces  of  alum,  and 
14  ounces  of  whiting.  In  this  process  is  not  explained 
the  utility  of  starch  and  whiting,  and  the  materials 
used  are  too  costly  to  permit  their  employment  in  the 
practice. 

Thompson's  Process. — The  composition  used  by  this 
tanner  is  the  following : — 

Polygonum  bistorta  ...  10  lbs. 

Geranium  maeulatum  ...  2  “ 

Sulphate  of  copper  ...  i  “ 

Catechu  in  weak  solution  .  .  1  bbl. 

Instead  of  catechu,  tan  bark  or  hot  water  can  be 
used. 

L.  Robinson's  Process. — This  process  consists  in  the 
employment  in  combination  with  catechu,  which  has 
been  purified  by  sulphuric  acid,  of  carbonate,  sulphate, 
or  calcined  magnesia,  and  sulphate  of  potash,  for  the 
purpose  of  tanning  hides  of  every  description. 

T.  G.  Eggleston's  Process. — This  process  is  similar  to 
the  above,  and  wre  do  not  think  them  worthy  of  con¬ 
sideration,  as  being  impossible  in  large  tanneries.  The 
author  uses  terra  japonica  purified  by  sulphuric  acid,  in 
conjunction  with  carbonate  and  sulphate  of  magnesia, 


QUICK  TANNING 


401 


and  sulphate  of  potash.  He  prepares  the  tanning  liquid 
called  No.  1,  with — 

Water  .  .  .  .  .  112  galls. 

Terra  japonica  ....  15  lbs. 

He  stirs  until  dissolved,  and  adds — 

Sulphuric  acid  ....  3  lbs. 

Stir  well,  leave  to  cool  and  decant. 

For  upper  leather,  to  the  above  quantity  of  the 
liquor  he  adds  ^  of  an  ounce  of  carbonate  of  magnesia, 
and  Jg  of  an  ounce  of  sulphate  of  potash,  and  as 
much  water  to  reduce  the  liquor  No.  1  to  one-half  its 
strength. 

This  liquor  is  good  for  ten  good  sized  hides.  The 
hides  are  put  in  and  well  stirred  during  the  first  two 
days.  He  keeps  always  the  liquor  No.  1  prepared,  so 
as  to  increase  the  strength  of  the  vat.  Thirty-five  gal¬ 
lons  are  added  every  second  day,  with  1  ounce  of  sul¬ 
phate  of  magnesia.  The  hides  are  raised  up  to  put  in 
the  fresh  liquors.  The  operation  is  continued  until  the 
skins  are  tanned. 

This  method  is  good  for  every  skin  the  hair  of  which 
has  been  removed.  According  to  its  author,  this  process 
is  a  little  quicker  than  the  ordinary  one,  and  the  leather 
is  better. 

A.  Dietz’s  Process. — The  features  of  this  invention 
consist  in  swelling  the  tissues  and  fibres  of  the  skin 
previous  to  and  during  the  process  of  tanning,  by  the 
use  of  saline  liquors,  so  as  to  fit  the  skin  to  receive 
most  easily  and  effectually  the  tanning  material,  and  in 
using  in  connection  with  such  saline  liquors,  tanning 
liquors  of  different  and  increasing  strength,  whereby 
the  centre  and  inner  parts  of  the  skin  are  tanned  as 
quickly,  or  nearly  so,  as  the  outer  surfaces. 

The  author  makes  a  weak  liquor,  at  2°  or  3°  by  the 
barkometer,  from  any  tanning  material ;  in  such  liquor 
he  mixes  salt  or  alum,  two  ounces  to  the  gallon,  stirs 
well  the  whole ;  immerses  the  skins  in  this  liquor  and 
handles  them  till  they  are  well  saturated  and  the  fibre 
fully  swollen.  The  saline  substance  may  be  dissolved 

26 


402 


TANNING. 


in  water  alone  without  any  tannic  material,  and  the 
skins  saturated  with  this  liquor,  and  after  being  com¬ 
pletely  saturated  they  are  passed  in  the  tanning  bath. 

The  strength  of  the  bath  in  tannin  has  to  be  increased 
from  2  to  4  every  day,  and  the  skins  are  stirred  and 
handled  until  they  are  tanned. 

The  time  required  to  tan  is  the  following : — 

Sheep-skin  .  .  .  .  2  or  3  days. 

Calf  “  .  .  .  .  8  days. 

Heavy  leather  .  .  .  30  to  40  days. 

Sole  leather  .  .  .  40  to  50  days. 

P.  Daniel’s  Process. — The  author  prepares  a  bath  of 
terra  japonica  at  10°. 

The  first  day  for  30  skins  he  makes  a  bath  with  8 
ounces  of  tartaric  acid ;  he  immerses  the  hides  in  and 
handles  them  four  or  five  times.  The  second  day  he 
takes  half  a  pail  of  the  tannin  solution,  he  dissolves  \ 
a  pound  of  sal  soda  and  adds  to  it  a  quarter  of  a  pound 
of  tartaric  acid ;  stirs  well  and  puts  in  the  vat  contain¬ 
ing  the  tannin  solution,  and  repeats  the  operation  as 
often  as  requisite. 

In  the  last  week  he  adds  a  quarter  of  a  pound  of 
bi-chromate  of  potash,  and  the  leather  is  finished  in  the 
usual  manner. 

Whatever  are  the  merits  of  this  process,  the  use  of 
tartaric  acid,  on  account  of  its  high  price,  renders  this 
method  impossible  in  practice ;  and  in  addition  we  can 
never  recommend  the  use  of  bi-chromate  of  potash  on 
account  of  its  oxidizing  action  on  organic  substances. 

D.  Needhams  Process. — The  following  bath  is  pre¬ 
pared  : — 

Hempseed  .....  1  peck. 

Hops . 1  lb. 

Sal  soda  .  .  .  .  .  .  f  “ 

Animal  brain  .  .  .  .  .  f  “ 

The  whole  is  boiled  in  8  gallons  of  water.  When 
ready  it  is  diluted  with  40  gallons  of  water. 

The  hides  are  soaked  in  this  solution  from  6  to  36 
hours.  Then  they  are  put  in  a  tanning  solution  con¬ 
sisting  of — 


QUICK  TANNING. 


403 


Catechu  . 
Divi-divi  . 
Alum 
Salt 


12  lbs. 
4  “ 

4  “ 

2  “ 


The  originality  of  this  process  consists  in  the  applica¬ 
tion  to  the  hides  of  the  above  solutions,  preparatory  to 
treating  them  with  the  tanning  liquor. - 
R.  Harper  s  Process. — The  author  takes — 

Wormseed  .....  50  lbs. 

Thoroughwort  .  .  .  .  50  “ 

Boneset  .  .  .  .  .  50  “ 

Goldenwort  .  .  .  .  .  50  “ 


He  makes  a  liquor  by  steaming  them,  and  uses  this 
liquor  in  connection  with — 

Terra  japonica  ....  15  lbs. 

Alum . 10  “ 

Saltpetre  .....  1  “ 

These  quantities  are  for  100  skins.  According  to  its 
author,  the  use  of  the  above-mentioned  weeds,  in  com¬ 
bination  with  the  aforesaid  drugs,  facilitates  the  process 
of  tanning,  and  is  cheaper  than  the  usual  process  with 
bark. 

Our  opinion  is  different.  This  process  is  more  costly, 
and  the  leather  must  be  of  inferior  quality  to  that  made 
from  bark,  and  this  is  easily  accounted  for,  the  above 
weeds  containing  very  little  tannin  and  much  extractive 
matter. 

A.  Hill's  Process. — He  takes — 


Soda 

1  lb. 

Gum  tragacanth 

1  “ 

Terra,  japonica 

.  12  lbs. 

Alum 

4  “ 

Common  salt 

3  “ 

Saltpetre 

i  lb. 

Prussiate  of  potash 

•  4 

He  dissolves  in  water,  and  leaves  the  hides  in  for  ten 
days.  We  hardly  believe  such  a  mixture  will  work,  and 
we  do  not  see  the  necessity  of  using  alum  in  connection 
with  the  prussiate  of  potash,  which  will  render  the  pro¬ 
cess  unhealthy  on  account  of  the  prussic  acid  disengaged; 


404 


TANNING. 


and,  besides  this  inconvenience,  the  materials  used  are 
too  costly. 

J.  Nuessley's  Process. — He  takes — 

Pyroligneous  acid,  from  wood-tar,  properly 


obtained  by  distillation  .  .  1  gall. 

Water . 3  galls. 

Hydrochloric  acid  .  .  .  .  4  oz. 

Catechu  .  .  .  .  .  .  1|  lb. 

Alum  ......  |  “ 


He  mixes  the  acid  with  the  water  and  adds  the  hydro¬ 
chloric  acid  to  the  solution.  Stir  well. 

For  100  gallons  of  the  above,  he  adds — 

Catechu  . . 40  lbs. 

Alum  . 10  “ 

And  when  cold  put  the  hide  in  this  bath.  In  three 
or  four  days  the  skin  is  tanned ;  heavy  skins  require 
three  or  four  weeks. 

M.  A.  Bell’s  Process. — The  hair  is  removed  and  the 
skins  are  prepared  in  the  usual  manner.  They  are  im¬ 
mersed  in  the  tanning  liquor  from  two  to  four  days. 
The  tanning  liquor  is  prepared  as  follows : — 

Wood  ashes  ....  1  bushel. 

Water  ......  50  galls. 

Let  to  settle  and  draw  .  .  40  “ 

He  adds  40  lbs.  of  terra  japonica,  and  boils  until  dis¬ 
solved.  He  allows  to  cool,  decants,  and  it  is  ready  for 
use. 

The  author  claims  in  this  process  that,  by  the  combi¬ 
nation  of  lye  with  tannin,  he  is  enabled  to  prevent  the 
tanning  liquors  becoming  sour  or  decomposed,  and  he 
is  enabled  to  strengthen  them  without  accumulating 
more  than  is  necessary,  and  will  tan  skin  in  a  shorter 
time  and  with  less  labor  than  by  any  other  known 
process. 

Blet's  Process. — He  operates  in  vats  of  oak  or  pine 
wood,  which  are  kept  in  a  room,  the  temperature  of 
which  is  always  between  77°  and  86°.  The  hides  are 
put  into  a  vat  containing  river  water;  for  1000  lbs.  of 
leather  the  vat  contains  63  galls,  of  water  and  5  lbs.  of 
urea.  Raise  the  hides  four  times  a  day ;  after  three 


QUICK  TANNING. 


405 


days  the  hides  are  well  peeled,  then  they  are  well 
worked  with  a  stone  bottle,  and  immediately  after  they 
are  peeled  they  are  thrown  into  water  and  put  anew  in 
the  vat  with  5  lbs.  of  urea;  let  run  on  them  tan  juice 
strong  enough  ;  raise  four  times  a  day,  adding  every  day 
some  new  tan  juice  stronger  and  stronger.  Fifteen  days 
after  put  them  into  a  vat  with  water,  and  the  juice  which 
has  been  used  to  raise  them.  Six  weeks  after  the  hides 
are  tanned. 

Baron’s  Process.— The  river  work  and  depilation  by 
lime  are  the  same  as  in  the  ordinary  process,  only  that 
the  author  passes  the  hides  during  three  hours  in  river 
water  containing  joVo  °f  spirit  of  salt  (hydrochloric 
acid,  to  destroy  the  small  quantity  of  lime  the  skins  may 
contain,  and  afterwards  he  washes  in  river  water.  This 
treatment  with  the  acid  terminates  the  perfect  swelling 
of  the  hides,  and  they  are  ready  to  be  tanned. 

Before  tanning  the  color  of  the  leather  must  be  fixed 
so  as  to  be  of  the  usual  shade.  For  that  purpose  he 
prepares  a  juice  of  oak  bark,  at  1°  of  the  barkometer; 
in  this  juice  he  dissolves  of  madder,  and  passes  the 
hides  in  this  bath  for  six  hours,  so  as  to  have  the  color 
take  evenly.  He  leaves  to  rest  one  hour,  and  turns 
them  over  every  hour. 

Twenty-four  hours  after  the  hides  are  ready  to  be 
tanned  in  the  following  manner :  In  river  water  dissolve 
catechu  according  to  the  number  of  hides  to  tan.  The 
liquor  is  placed  in  a  receiver,  covered  with  a  filter,  and 
provided  with  a  rubber  pipe  to  transfer  the  juice  to  the 
vats. 

The  first  vat  contains  juice  at  1°,  with  a  weak  solu¬ 
tion  of  alum  :  the  hides  are  put  in  this  mixture  and  are 
occasionally  stirred  during  the  first  hours,  afterwards 
they  are  raised  every  three  hours.  Next  day  they  are 
placed  in  a  vat  containing  juice  at  2°.  Raise  four  times 
a  day,  and  let  them  drain  two  hours ;  increase  the 
strength  from  day  to  day  until  the  hides  are  well  tanned. 
Complete  in  the  usual  manner. 

Quick  Process. — In  this  process  the  vessel  has  to  be 
air-tight,  and,  at  the  same  time,  no  metal  can  be  used 


406 


TANNING. 


but  copper.  When  the  hides  are  taken  from  the  wash 
all  the  water  is  expelled  by  pressure,  they  are  then 
packed  in  a  barrel,  fixed  so  as  to  have  a  rotary  motion, 
and  with  them  the  necessary  amount  of  tanning  mate 
rial  is  mixed,  and  enough  water  is  added  to  keep  moist 
the  contents  of  the  barrels.  The  main  hole  of  the  bar¬ 
rel  is  now  closed,  and  the  air  pumped  out  as  completely 
as  possible ;  this  being  done  the  stopcock  is  closed,  and 
a  piece  of  lead  pipe  is  added  to  the  conducting  tube. 
This  lead  pipe  communicates  with  a  tank  containing  a 
solution  of  tanning  material  of  the  proper  strength.  If 
the  stopcock  is  now  opened  the  tanning  fluid  rushes 
rapidly  into  the  barrel,  and  when  a  sufficient  quantity 
has  been  admitted  the  stopcock  is  closed,  and  the  bar¬ 
rel  is  now  rotated  for  one  hour,  or  half  an  hour,  accord¬ 
ing  to  the  quantity  of  hides  contained  in  it.  After  two 
or  three  hours’  rest  the  rotation  is  again  continued,  until 
the  operation  is  completed.  The  advantages  of  this 
process  are  to  open  the  pores  of  the  skins,  and  the  tannin 
is  not  converted  so  quickly  into  gallic  acid. 

The  rotary  motion  facilitates  the  absorption  of  the 
tannic  acid  from  the  bark,  and  helps  its  absorption  by 
the  hides,  which  are  then  tanned  in  less  time  than  with¬ 
out  rotary  motion,  as  shown  in  the  following  table: — 

Time  required  for  tanning  Time  required  for  tanning 
in  vacuo  without  motion.  in  vacuo  with  motion. 

Calf  skins,  from  .  6  to  11  days  .  .  4  to  1  days. 

Horse  hides  .  35  to  40  “  .  .  14  to  18  “ 

Lighter  hides  .  30  to  35  “  .  12  to  16  “ 

Cow  hides  (middling)  40  to  45  “  .  .18  to  20  “ 

“  (heavy)  50  to  60  “  .  .  22  to  30  “ 

Ox  hides  (light)  50  to  60  44  .  .  20  to  30  “ 

“  (first quality)  70  to  90  “  .  .  35  to  40  “ 

In  this  process  a  large  percentage  of  bark  is  saved. 
Guiot's  Process. — The  hides  are  swelled  and  depilated 
as  usual.  A  vat  containing  50  hides  has  the  following  • 
dimensions:  3  feet  wide  and  4i  feet  high.  The  propor¬ 
tions  of  material  to  use  are,  for  50  hides  weighing  500 
lbs. : — 

Catechu  .....  150  lbs. 

Water . 50  galls. 

Stir  well  until  dissolved,  and  add  50  galls,  of  fresh  water,  and  a 
solution  containing  3  lbs.  of  lime.  Mix  the  whole. 


RESIDUES  AND  PRODUCT  OF  TANNERIES. 


407 


Put  the  hides  in  this  bath  and  leave  them  in  for  eight 
weeks.  During  the  first  two  weeks  raise  them  once  a 
day ;  the  last  6  weeks  raise  them  only  once  a  week. 
Prepare  another  bath,  and  for  this  purpose  take  25  galls, 
of  the  above  which  has  been  used,  25  galls,  of  fresh  water, 
and  6  lbs.  of  white  vitriol ;  mix,  put  the  hides  in  and 
leave  them  4  days,  being  careful  to  stir  every  day.  Raise 
and  put  them  in  125  galls,  of  fresh  water,  leave  them  in 
for  three  days  and  then  they  are  perfect.  Complete 
them  in  the  usual  manner. 


CHAPTER  Cl. 

RESIDUES  AND  PRODUCT  OF  TANNERIES. 

Tanners  call  waste  or  residue,  1.  The  cuts  and  other 
parts  of  skins  which  being  of  any  use  are  employed  to 
make  glue.  2.  The  wadding,  horns,  hair,  spent  tan,  and 
old  lime. 

The  glue,  or  the  cuts,  is  sold  according  to  the  quality  ; 
those  of  calf  are  always  considered  the  best  for  the  fab¬ 
rication  of  glue. 

Mr.  De  La  Laude  has  advanced  that  cuts  from  skins 
prepared  with  tan  juice  were  not  fit  to  prepare  glue. 
It  is  a  mistake,  for  in  Paris  where  heavy  leathers  are 
prepared  in  this  manner,  the  cuts  are  sold  for  this 
purpose. 

The  hairs,  when  they  are  mixed,  are  sold  in  France, 
from  $2  40  to  $3  00  the  hundred  weight.  Those  of  calf 
without  any  mixture  are  sold  for  $3  60  the  hundred. 

The  horns  are  sold  by  the  hundred,  according  to  their 
size  and  length.  The  old  lime  can  be  used  for  fence 
walls  and  even  for  foundations,  or  for  manure. 

The  spent  bark  can  be  used  by  gardeners  for  hot-beds 
and  hot-houses.  In  France  it  is  sold  for  this  purpose  by 
the  wagonful  at  the  rate  of  $1  00  to  $1  20. 

According  to  Mr.  De  La  Laude,  50  leathers  prepared 
with  lime  give  yearly  a  product  of  66  francs  ($13  20), 
the  same  quantity  of  leather  prepared  with  barley  211 


408 


TANNING. 


francs  ($42  20),  and  at  last  50  leathers  prepared  with 
infusion  of  tan  produce  254  francs  ($50  80). 

A  hide  weighing  100  lbs.,  after  being  separated  from 
the  horns,  hair,  blood,  grease,  etc.,  gave  by  tanning  55 
lbs.  of  leather,  sold  at  about  30  cts.  per  lb.  Thus  a  hide 
of  100  lbs.  cost  $7  00,  and  is  sold  for  $16  50. 

The  industry  of  tanning  gives  a  great  value  to  the 
woods  for  the  use  of  the  bark.  The  price  of  the  bark 
extracted  from  one  hectare  (2i  acres)  of  wood  is  valued 
at  $30  00. 


PART  III. 

CUEEYIN  Gf. 


SECTION  VIII. 

GENERAL  WORK  OF  THE  CURRIER. 

The  derivation  of  Currier  is  from  the  Latin  Corrigere, 
which  means  straighten,  weaken,  etc.,  or  better,  from 
Coriarus,  workman  who  works  leather,  called  Corium  by 
Latins.  The  ancients,  as  with  us,  understood  by  currying 
the  art  of  working  or  continuing  to  work  tanned  skins 
or  leathers  to  give  them  suppleness,  polish,  color,  etc., 
according  to  the  use  for  which  they  were  destined.  If 
the  art  of  tanning  has  necessarily  preceded  the  art  of 
currying,  it  is  easy  to  ascertain  that  currying  has  cre¬ 
ated  the  arts  of  the  harness-maker,  shoemaker,  carriage- 
maker,  etc. 

Of  old,  the  currier  applied  himself  only  to  hides  of 
small  oxen,  cows,  calves,  goats,  and  sheep.  Horse  and 
mule  hides  were  the  lot  of  the  Hungarian  tanners,  who 
alumed  them,  and  passed  them  to  tallow  to  manufacture 
the  so-called  German  leather.  Now  these  hides  are  cur¬ 
ried,  and  the  leathers  they  produce  take  the  place  of 
goat  and  sheep-skins  for  upper  leathers  and  boot  legs. 

We  must  observe  that,  of  old,  curriers  gave  the  name 
of  cow-hides  to  small  ox-hides,  which  will  not  produce 
strong  leather,  while  now  they  distinguish  the  hides 
by  the  name  of  ox,  cow,  etc.  It  is  a  known  fact  that 
cow-hides  are  to  be  preferred  for  currying  to  those  of 
young  oxen.  Curried  leathers  have  different  names, 
according  to  their  preparation  and  their  use.  The  prin¬ 
cipal  are  tallowed  leather ,  oiled  leather ,  waxed  leather , 


410 


CURRYING. 


oiled  cow,  etc.  The  principal  operations  to  which  leathers 
are  submitted  are  the  following:  Soaking  or  dipping, 
treading  or  beating,  stretching,  oiling,  tallowing,  dyeing, 
and  polishing.  But  before  working  them,  the  tails,  fore¬ 
heads,  teats,  and  parts  of  the  extremities  are  cut  off,  and 
these  remnants  are  used  for  uppers,  soles,  heels,  etc. 

According  to  some  manufacturers,  there  are  some 
places  where  they  work  heavy  leathers  with  the  pommel. 
This  process,  which  can  be  used  only  when  the  leathers 
are  damp,  strengthens  them  and  renders  them  finer. 
However,  this  work  being  very  hard,  we  indicate  it 
without  advising  its  use.  In  some  countries  curriers  pass 
strong  leathers  in  tallow  and  render  them  water-proof. 
The  only  objection  to  this  process  is  that  it  is  too  long 
and  difficult. 


CHAPTER  CII. 

DIPPING. 

\ 

The  first  operation  of  the  currier  is  that  of  dipping  or 
softening  leather.  For  this  purpose,  after  cutting  off  the 
tails,  foreheads  and  teats,  they  are  put  in  a  tub  in  which 
they  stay  until  they  are  sufficiently  moist  to  be  worked. 
Of  old  the  curriers  used  to  dip  a  broom  in  water  and 
sprinkle  the  leather  until  it  was  completely  moistened. 


Fig.  111. 


When  the  skin  is  well  moistened,  it  is  placed  on  the 
ground  in  a  clean  place,  or  better  on  a  hurdle,  and  it  is 
beaten  with  the  feet  until  the  water  has  penetrated  all 
its  parts  and  it  has  become  supple.  That  hurdle  is  rep¬ 
resented  in  Fig.  117. 


DIPPING. 


411 


There  are  two  kinds:  one,  manufactured  by  basket- 
makers,  is  composed  of  two  strong  posts  about  one  yard 
long.  In  each  post  make  seven  or  eight  holes  equally 
spaced,  in  which  you  introduce  strong  sticks  to  keep 
them  spaced  about  a  yard.  Between  these  sticks  inter¬ 
lace  some  ashed  sticks.  The  other  kind  is  made  by  a 
carpenter.  It  is  formed  with  15  strong  posts;  seven 
of  them  are  placed  below  at  equal  distances,  and  eight 
above,  notched  to  a  Avood  and  screwed  to  each  other. 
These  posts  form  eight  ranks  of  parallel  lines  in  one 
way,  crossed  at  right  angles  by  eight  other  ranks  of  par¬ 
allel  lines,  leaving  between  each  empty  spaces  of  about 
3  inches  square.  The  workman  to  beat  the  leather  wears 
large  shoes  made  for  this  purpose,  with  three 
thicknesses  of  soles.  For  a  quarter  of  an  Fig.  118. 

hour  or  longer,  with  the  heels  the  workman  _ a.. 

tramples  upon  the  leather  in  every  direction. 

The  left  foot  maintains  the  leather  firm,  while 
the  right  heel  pushes  it  with  great  force.  For  this  pur¬ 
pose  is  also  used  a  mace  with  a  handle  114  feet  long, 
Avith  a  mallet  4t7q  inches  long,  51  inches  square,  upon 
the  two  faces  of  Avhich,  parallel  to  the  lines  of  the  handle, 
are  four  egg-shaped  pegs  of  Avood,  one  and  a  half  inches 
in  length,  Avhich  are  finely  polished,  so  as  not  to  tear  the 
moistened  leather  Avhen  beaten  with  it.  Experiment 
has  demonstrated  that  all  the  skins  destined 
to  be  talloAved,  not  only  ought  to  be  beaten 
by  the  feet,  but  also  rounded,  and  these  tAvo 
operations  require  more  care  where  the  skins 
are  hard  and  difficult  to  work.  Firm  skins 
require  to  be  more  humected  than  others;  it 
is  the  same  for  all  the  dry  parts  of  these  same 
skins.  It  is  a  bad  process  to  moisten  Avith  a 
broom;  they  are  much  better  done  when 
dipped  in  a  tub. 

The  leather,  after  having  been  properly 
softed  by  these  means,  is  placed  upon  the  horse  and  sub¬ 
jected  to  the  action  of  the  cleaners.  The  horse  consists 
of  a  strong  firm  flat  board,  supported  upon  a  frame  by 
two  uprights  and  a  cross-piece,  so  that  it  can  be  made 


Fig.  119. 


412 


CURRYING. 


to  slope  at  a  greater  or  less  angle.  If  not  sufficiently 
heavy  to  be  immovable,  it  may  be  loaded  with  weights 
placed  upon  the  frame. 


Fig.  120. 


A  more  convenient  beam  is  that  patented  by  N.  Sar¬ 
gent.  The  upright  is  filled  with  adjusting  screws,  by 
which  it  may  be  elevated  or  lowered  to  any  desired 
height,  as  may  suit  the  comfort  and  convenience  of  the 
workman. 


Fig.  121. 


Formerly,  and  in  some  places  now,  three  instruments 
have  been  and  are  used  for  cleaning  and  paring  the 
leather:  the  sharp  edge  cleaner,  the  blunt  cleaner,  and 
the  head  knife.  The  latter  alone  is  now  used  in  Paris 
for  this  first  working.  This  knife,  called  in  French  cou- 
teau  a  revers ,  on  account  of  the  form  of  its  edge,  which 
is  very  much  turned  over,  is  from  12  to  14 
Fig.  122.  inches  long,  and  from  4i  to  5i  inches  broad, 
and  has  two  handles,  one  in  the  direction 
of  the  blade,  and  the  other  perpendicular 


SHAVING. 


413 


to  it,  for  the  purpose  of  guiding  the  edge  more  correctly 
over  the  surface  of  the  skin. 

The  round  knife  ( lunette )  is  a  circular  knife  from  ten 
to  twelve  inches  in  diameter,  with  a  round  4  or  5  inch 
hole  in  the  centre,  for  introducing  the  hands.  It  is  con¬ 
cave,  of  the  form  of  a  spherical  zone;  the  concave  part 
being  that  which  is  applied  to  the  skin,  and  having  an 
edge  a  little  turned  over  on  the  side  opposite  to  the  skin, 
so  as  to  prevent  it  from  entering  too  far  into  the  leather. 
Besides  these,  the  sharp-edged  and  blunt-edged  cleaners 
are  sometimes  used.  The  latter  is  usually 
made  of  an  old  knife,  and  is  provided  with  Fig.  123. 
two  handles ;  the  former  may  be  made  of  r— >ie»^ 
an  old  sword. 

Curriers  are  recommended  to  dispense  with  these 
cleaners,  to  use  the  head  and  round  knife  for  shaving 
and  paring  the  skins  upon  the  horse,  and  to  confine 
themselves  to  the  employment  of  the  stretching-iron  for 
smoothing  and  scraping  the  leather,  for  filling  up  its 
weak  parts,  removing  the  creases,  and  the  filamentous 
particles  which  project  from  its  surface. 


CHAPTER  CIII. 

SHAVING. 

The  second  operation  of  the  currier  is  to  shave  the 
skins  with  the  head-knife,  above  described.  When  the 
leather  has  been  smoothed,  it  is  shaved  to  secure  uni¬ 
formity  of  thickness  and  regularity  of  surface,  and  that 
is  the  reason  why  every  cow-skin  which  is  destined  to 
be  tallowed  or  oiled  must  be  shaved.  When  weak  and 
thin  parts  are  found  in  the  leather,  this  operation  is 
dispensed  with;  they  are  filled  up  with  the  stretching- 
iron. 

The  head-knife  is  the  only  one  used  for  calf  and  sheep¬ 
skins.  Parisian  curriers  shave  with  the  round-knife  and 
head-knife.  They  use  the  French  horse  for  paring  off 
the  borders  of  the  skins,  and  the  English  horse  for  the 
other  operations. 


414 


CURRYING. 


For  the  purpose  of  paring  with  the  round-knife  the 
French  horse  is  used  also.  However,  in  nearly  all  the 

Fig.  124. 


shops,  the  table  has  been  substituted  for  the  horse,  and 
it  is  on  the  table  that  the  leather  is  smoothed. 

The  above  represents  the  workman  smoothing  the 
leather. 


CHAPTER  CIV 

POMMELING. 

All  kinds  of  leather  should  be  submitted  to  the  action 
of  the  pommel,  so-called  because  it  clothes  the  hand  and 
performs  its  functions.  This  instrument  has  a  rectangu¬ 
lar  shape,  and  is  of  different  sizes,  but  is  generally  about 
13  inches  long  and  5  broad,  and  is  made  of  dogwood. 
The  upper  surface  is  flat,  and  provided  with  a  wide 
leather  strap  nailed  to  the  sides,  which  is  intended  for 
confining  the  hand  of  the  workman.  The  lower  surface 
is  rounded  and  furrowed  over  with  transverse  straight 
ridges  and  grooves.  These  grooves  are  sharp-edged 
isosceles  triangles  in  section,  and  vary  in  fineness  accord¬ 
ing  to  the  size  of  the  pommel,  the  largest  being  from 
seven-hundredths  to  one-fifth  of  an  inch  deep,  and  two 
or  three-tenths  of  an  inch  wide. 


Fig.  125.  Fig.  126. 


A  large  kind  of  pommel,  called  the  marguerite,  is  now 
employed  for  nearly  all  the  operations  in  which  the  or¬ 
dinary  one  was  formerly  used.  It  is  from  15  to  19 


STRETCHING. 


415 


Fig.  127. 


jOQ 


inches  long,  5  inches  broad,  and  of  a  thick¬ 
ness  in  the  middle  of  from  3|  to  4|  inches, 
and  at  the  end  of  from  one  and  nine-tenths 
to  two  and  two-tenths  inches.  As  it  is 
much  heavier  and  more  difficult  to  manage  than  the 


pommel,  a  peg  or  handle  is  placed  at  one  end  for  the 
workman  to  grasp,  while  his  arm  is  placed  under  a  large 
strap,  and  his  elbow  rests  upon  a  cushion  at  the  other 
end.  The  grooves  are  larger  and  further  apart  than 
those  of  pommels,  and  differ  in  size  with  that  of  the 
marguerite,  which  may  be  made  for  particular  purposes, 
larger  or  smaller  than  the  one  which  has  been  described. 

These  instruments  are  those  which  are  the  best 
adapted  to  the  purpose  of  giving  flexibility  and  a  granular 
appearance  to  the  leather.  The  skin  is  first  folded  with 
its  grain  side  in  contact,  then  stretched  out  upon  a  table, 
and  rubbed  strongly  with  the  pommel,  or  marguerite ,  each 
quarter  successively  being  made  to  slide  under  the  in¬ 
strument,  over  the  leather  below  it,  first  towards  the 
centre,  and  then  back  to  its  original  position.  This  mode 
of  working  leather  makes  it  extremely  flexible.  To  give 
the  proper  grain,  the  skin  is  then  stretched  out  upon  the 
flesh  side,  and  pommelled  from  head  to  tail  and  cross¬ 
wise. 


CHAPTER  CV. 

STRETCHING. 

This  operation  is  performed  with  the  stretching-iron, 
which  is  a  flat  piece  of  thin  iron  or  copper,  a  fourth  of 
an  inch  thick  at  the  top,  and  thinning  off  at  the  bottom 
into  a  blunt  edge,  shaped  like  an  arc  of  a  very  large 


Fig.  128.  Fig.  129. 


circle.  It  is  about  6  inches  long  and  4  inches  high,  and 
is  provided  with  a  handle  ten  inches  in  length  and  five 


416 


CURRYING. 


in  height.  An  iron  or  steel  instrument  is  generally  em¬ 
ployed,  as  being  less  likely  to  wear  out  than  a  copper 
one ;  but  the  latter  is  preferred  by  many,  since  the 
leather  is  sometimes  blackened  and  spotted  by  the  iron. 
One  made  of  steel  is  less  objectionable  on  this  account. 
Stretchers  of  other  forms  and  dimensions  than  the  one 
described  above  are  sometimes  used,  but  they  vary  very 
little  from  each  other  in  construction.  Those  formerly 
used  were  without  handles,  and  had  a  copper  rim  to  pro¬ 
tect  the  hands  of  the  workman. 


Fig.  130. 


The  skin  being  placed  upon  a  table,  the  workman 
grasps  the  stretching  iron  in  both  hands  (central  figure), 
and  holding  it  nearly  perpendicular  upon  the  leather, 
forcibly  scrapes  the  thick  places  so  as  to  render  them  of 
uniform  thickness  with  the  rest,  to  remove  particles  of 
flesh  or  projecting  filaments,  and  to  fill  up  the  thin  and 
weak  spots.  The  leather  is  rendered  smoother,  softer, 
more  compact,  and  equal  throughout  by  this  operation, 
to  which  all  kinds  of  skins  should  be  subjected;  and 
when  thus  treated,  there  is  no  absolute  need  of  the  ap¬ 
plication  to  them  of  oil  or  tallow. 


WORKING  WITH  THE  ROUND-KNIFE. 


417 


CHAPTER  CVI. 

WORKING  WITH  THE  ROUND-KNIFE. 

The  round-knife,  as  shown  in  the  figure  below,  has 
already  been  described..  The  leather  is  submitted  to 
its  action  after  its  edges  have  been  sloped  off 
with  the  head-knife,  an  operation  which  is  per-  Fig-  131. 
formed  upon  the  horse  by  shaving  off  a  layer  ARA 
of  two  inches  in  breadth  all  around  the  borders 
of  the  skin.  They  are  then  worked,  with  the 
round-knife  upon  the  dresser ,  a  cylindrical  wooden  bar 
fastened  at  a  height  of  five  feet  three  inches  from  the 
ground,  by  its  two  ends,  to  two  buttresses  projecting 
from  the  wall. 

Along  the  upper  surface  of  this  bar  a  thick  cord  is 
stretched.  Separate  the  end  from  the  dresser,  fold  the 
breadth  of  the  skin  over  it,  the  grain  being  within,  turn 
over  the  skin  and  stretch  it  around  the  beam,  its  end 
being  firmly  held  between  the  bar  and  the  cord,  which 
is  still  more  tightly  pressed  down  by  the  leather  which 
envelops  it.  The  figure  below  represents  a  skin  stretched 
upon  the  dresser. 


Fig.  132. 


After  the  skin  is  stretched,  the  lower  part  of  it  is 
seized  and  confined  in  place  by  a  pair  of  pincers  at¬ 
tached  to  the  girdle  of  the  workman,  and  grasping  the 
round-knife  with  both  hands,  he  works  the  leather  with 
it  from  above  downwards,  removing  the  fleshy,  thick,  or 
projecting  parts.  This  paring  requires  the  utmost  care, 
and  is  generally  done  from  tail  to  head,  and  sometimes 
across  the  grain. 

The  round-knife  is  occasionally  sharpened  upon  an 

27 


418 


CURRYING. 


oiled  stone,  and  the  edge  is  kept  turned  over  by  a  steel, 
so  as  to  prevent  it  from  entering  too  far  into  the  leather. 


Fig.  133. 


This  operation  is  performed  only  or  chiefly  in  France 
for  goat-skins,  all  the  other  kinds  being  pared  with  the 


Fig.  134. 


head-knife.  An  ordinary  skin  can  be  pared  upon  the 
dresser  in  one  hour,  and  six  or  eight  dozen  goat-skins 
in  a  day.  Before  being  curried,  hides  are  frequently 
cut  in  half,  and  are  still  oftener  made  in  an  almost 
square  form  by  cutting  off  the  head  and  belly  parts, 
leaving  the  tail  still  attached  to  them.  These  square 
hides  contain  all  the  best  and  strongest  parts  of  the 
leather ;  the  head  and  belly  portions  being  the  weakest, 
and  only  used  by  shoemakers  for  the  finest  or  upper 
soles. 


CHAPTER  CVII. 

PREPARATION  OF  STRETCHED  LEATHER. 

The  skins  of  cows  and  of  young  oxen  made  into 
crop-leather  are  the  only  ones  fit  for  stretchers ,  and  when 
thus  prepared  do  not  require  the  application  of  oil  or 
tallow. 


PREPARATION  OF  STRETCHED  LEATHER. 


419 


All  curriers  do  not  follow  the  same  method  ;  some 
preparing  the  crop-leather,  or  that  which  has  been  tan¬ 
ned  in  bags,  by  the  Danish  plan.  They  dry  the  leather, 
moisten  it,  flesh  on  the  horse,  moisten  a  second  time, 
scrape  with  the  stretcher,  and  when  thoroughly  dry, 
slick  it  with  the  glass  polisher  so  as  to  smooth  the  grain. 
Formerly  to  stretch  a  cow-skin  the  head  was  removed, 
as  being  too  thick  to  be  properly  smoothed ;  but  it  is 
now  usually  left  on,  as  it  forms  a  considerable  addition 
to  the  weight  of  the  leather.  The  skins  are  first  cut  in 
half  from  head  to  tail,  the  whole  skin  being  too  large 
to  be  properly  worked,  and  are  then  deposited  in  tubs 
full  of  water,  in  which  they  are  allowed  to  remain  for 
twelve  hours. 

When  thoroughly  wet,  they  are  taken  out  and  spread 
on  the  table  and  worked  from  head  to  tail  with  the 
stretching  iron,  or,  if  preferred,  they  are  lightly  pared 
on  the  horse.  These  operations  being  completed,  the 
skins  are  well  pommelled  and  worked  with  the  mar¬ 
guerite,  from  head  to  tail  and  crosswise,  and  then  dried. 

When  stretched  and  deprived  of  the  greatest  part  of 
their  moisture,  they  are  slightly  dampened  with  a  wet 
cloth  upon  the  hair  side,  and  scraped  again  with  the 
stretching  iron.  The  hair  side  is  well  moistened  with 
a  wet  cloth,  then  the  skins  are  dried,  placed  under  the 
press,  and  after  a  exposure  of  three  or  four  hours,  they 
are  hung  up  to  dry.  When  nearly  dry,  pile  them 
up  in  a  dry  and  clean  place,  cover  them  with  loaded 
planks,  and  the  operation  is  completed. 

Leather  prepared  in  this  way  does  not  require  oil  or 
tallow,  and  is  not  blackened.  It  is  used  by  saddlers, 
harness-makers,  and  shoemakers  for  the  soles  of  pumps, 
and  the  upper  soles  of  heavy  shoes. 


420 


CURRYING. 


CHAPTER  CYIII. 


PREPARATION  OF  SLEEKED  LEATHER. 

This  kind  is  principally  intended  for  saddlers’  and 
harness  makers’  use,  and  is  made  of  strong  hides.  Ox¬ 
hides  and  thick  cow-skins  are  generally  preferred. 

After  they  have  come  from  the  tanyard,  the  hides  are 
cut  in  two  and  are  deprived  of  the  head  parts,  soaked  in 
a  tub,  and  trod  out,  being  careful  not  to  allow  them  to 
become  too  thoroughly  saturated  with  water.  Then  they 
lightly  flesh  them  with  the  head  knife,  pommel  and  half 
dry  them  by  exposure  to  the  air.  In  this  state  they 
tread  them  out,  hang  them  up  to  dry  and  tread  put  a 
third  time;  pommel  on  both  sides,  and  at  last  hang 
them  up  until  thoroughly  dried.  Each  skin  then  has  its 
weight  marked  with  Roman  characters. 

Before  tallowing,  the  flesh  sides  are  rapidly  flamed, 
by  being  drawn  over  a  blaze  of  fire  from  lighted  straw, 
the  object  of  which  is  to  make  them  more  penetrable  to 
grease.  The  fatty  matter  to  be  used  is  left  to  the  choice 
of  the  operator,  but  mutton  suet  is  the  best,  and  gives  a 
finer  lustre  to  the  leather  than  any  other,  but  is  more 
expensive.  In  Paris  the  curriers  use  suet  obtained  from 
kitchen  drippings.  A  hide  of  an  ordinary  size  requires 
61  lbs.  of  suet. 

Melt  and  heat  the  grease  to  the  proper  point,  stretch 
the  skin  upon  the  table,  and  spread  the  tallow  over  the 
surface  with  a  tallowing  cloth  or  mop  made  of  the  fleecy 
parts  of  blanket  stuff.  This  kind  of  mop  is  15 
Fig.  135.  to  19  inches  long;  the  handle  is  made  by  bind¬ 
ing  or  tying  up  from  1 1  to  1 3  inches  of  its  length, 
leaving  a  tuft  long  enough  to  answer  the  purpose. 
Apply  at  first  the  grease  on  the  flesh  side,  and 
then  upon  the  grain,  and  more  of  it  is  rubbed  over  the 
groins,  edges,  and  thin  parts  than  over  the  rest,  so  as  to 
increase  their  strength  and  body.  A  hide  can  be  tal¬ 
lowed  in  five  minutes.  After  being  greased,  fold  the 
skins  square,  the  hair  side  in,  and  soak  in  a  tub  during 


PREPARATION  OF  SLEEKED  LEATHER. 


421 


eight  or  ten  hours;  then  tread  them  out  in  water,  and 
beat  with  the  mace  until  deprived  of  the  watery  con¬ 
tents.  Moisten  them  again  with  a  wet  broom,  or  soak 
for  a  time;  beat  once  more  in  every  direction.  Pommel 


Fig.  136. 


then  with  the  marguerite  upon  the  flesh  side;  the  hair 
side  is  pommelled  from  head  to  tail  and  crosswise,  until 
the  grain  is  well  smoothed,  then  the  skin  is  placed  upon 
the  table  with  the  hair  side  up,  and  the  surface  is 
smoothed  by  the  use  of  the  stretching-iron. 

Blacken  the  leather  now  while  still  upon  the  table; 
if  the  leather  has  become  too  dry,  moisten  it  before  the 
blackening,  because  a  certain  degree  of  humidity  is  ne¬ 
cessary  to  enable  it  to  receive  the  color.  For  this  pur¬ 
pose  dip  a  brush  of  horse  hair  in  the  composition  and 
rub  thoroughly  with  it  in  every  direction.  After  the 


•Fig.  137. 


first  blacking,  dry  the  leather  to  three  quarters,  by  ex¬ 
posing  it  to  the  air ;  pass  again  the  stretching  iron  over 
the  surface,  being  careful  not  to  scratch  it.  You  secure 
uniformity  and  smoothness  of  surface  by  moving  the 
instrument  constantly  in  one  direction.  To  make  the 


422 


GURRYING. 


leather  appear  thicker  and  uniform,  pare  off  the  edges 
with  a  hooked  knife. 


For  sleeked  leather  two  applica- 
Fig.  138.  tions  of  black  are  required,  and  if 

— any  part  of  the  surface  remains  of 
a  red  color,  a  third  may' be  requi¬ 
site.  The  second  coat  is  applied 
in  the  same  manner  as  the  first;  the  leather  is  then 
partially  dried,  and  the  surface  sleeked,  until  all  the 
marks  of  the  stretching-iron  have  disappeared.  When 
the  leather  is  of  a  fine  black  color  and  perfectly  dry, 
expose  it  to  the  press  for  two  weeks,  which  increases  its 
density  and  firmness,  the  excess  of  tallow  being  pressed 
out.  If  moist  when  placed  in  the  press,  it  is  usually 
found  covered  with  mould  when  taken  out. 

In  order  to  give  the  last  dressing,  wipe  the  hair  side 
well  so  as  to  remove  any  portions  of  remaining  grease, 
or  the  mould  formed  on  the  surface.  Polish  it  with  sour 
beer  or  barberry  juice,  and  sleek  the  surface  with  a  very 
smooth  stretching-iron. 


If  any  spots  of  grease  or  defects  remain  on  the  sur¬ 
face,  rub  gently  those  parts  with  a  cloth  dipped  in  the 
polishing  liquid,  until  perfectly  bright.  At  last  hang  up 
the  leather  to  dry  in  a  shady  place. 

Parisian  curriers  use  for  blacking  hatter’s  black,  com¬ 
posed  of  logwood,  nutgalls,  gum,  and  sulphate  of  iron. 
The  last  dye  is  made  as  follows ;  Cover  with  sour  beer, 
in  a  deep  wooden  vessel,  scraps  of  old  iron,  and  leave 
them  in  contact  for  three  months.  It  forms  a  red 
liquor  of  acetate  of  iron,  which  blackens  the  leather 
better  and  quicker  than  the  solution  of  sulphate  of  iron. 

Another  liquor,  less  expensive  and  more  quickly  make 
is  thus  prepared:  Mix  sour  beer  with  barley  yeast, 
leave  twenty-four  hours,  and  then  add  it  to  a  solution 
made  by  boiling  sulphate  of  iron  in  vinegar,  being  care¬ 
ful  to  remove  all  the  yeast  from  the  surface. 


COMPARISON  OF  SLEEK  LEATHER. 


423 


CHAPTER  CIX. 

COMPARISON  OF  SLEEK  LEATHER  WITH  ALUM-DRESSED 

LEATHER. 

Lately  the  Imperial  Board  of  Military  Horse  Inspec¬ 
tors  at  Vienna  put  the  questions  to  the  Austrian  Cham¬ 
bers  of  Commerce,  whether,  taking  into  consideration 
the  quality  and  nature  of  sleek  leather,  and  the  greater 
cost  of  articles  of  horse  gear  made  of  this  material,  more 
durability  was  possessed  by  it  than  by  alum-dressed 
leather  proportionally,  and  inquiring  as  to  what  per  cent, 
sleek  leather  excelled  alum  leather  on  this  head.  The 
questions  propounded  were  answered  as  follows: — 

“Although  the  various  articles  manufactured  out  of 
sleek  leather,  as  a  rule,  come  higher  in  price  by  at  least 
20  per  cent,  than  similar  articles  made  of  alum-dressed 
leather,  still  the  price  of  the  former,  in  view  of  their 
respective  qualities,  can  only  be  said  to  be  apparently 
higher,  for  which  reason  the  use  of  articles  made  of  sleek 
leather  is  to  be  recommended.  Alum-dressed  leather  is 
far  from  possessing  the  durability  of  sleek  leather,  and 
it  is  a  well-known  fact,  that  if  alum-dressed  leather  is 
exposed  to  humidity  it  grows  soft  and  therefore  ductile, 
by  which  when  the  horses  draw  the  traces  are  stretched 
out,  and  the  power  employed  to  set  the  load  in  motion 
is  weakened. 

“  On  this  account,  especially  for  the  harness  of  teams 
used  in  transportation  and  in  the  artillery  service,  where 
a  greater  amount  of  strength  is  necessary,  sleek  leather 
must  always  be  preferred  to  alum-dressed  leather. 

“And  even  if,  independent  of  what  we  have  already 
said,  the  articles  of  horse  gear  from  alum-dressed  leather 
do  come  cheaper,  still  this  economy  is  only  seeming  and 
not  real,  for  the  articles  made  from  sleek  leather  will 
generally  stand  almost  double  the  wear  of  those  made 
from  alum-dressed  leather,  and  therefore  they  are  in  fact 
worth  more,  by  at  least  20  or  30  per  cent. 

“  It  is  unnecessary  to  remark  on  what  account  sleek 


424 


CURRYING. 


leather  possesses  a  greater  durability  than  alum-dressed 
leather.  The  one  is  a  bark-tanned  leather,  the  other  a 
so-called  mineral-tanned  leather,  whose  pores  are  simply 
filled  out  with  the  material  in  an  insoluble  form,  and 
when  worked  upon  by  water  and  solvents  they  easily 
become  cleaned  out  again.  In  fact,  alum-dressed  leather 
when  exposed  merely  to  a  damp  air,  untans  itself ;  that 
is  to  say,  it  returns  to  its  original  raw  condition.  When 
bark-tanned  leather  happens  to  untan,  the  untanning  is 
a  very  slow  process  indeed,  because  the  combination 
formed  between  the  tanning  material  and  the  fibres  of 
the  hide  is  much  closer  and  firmer  than  in  the  other 
case,  where  merely  the  pores  of  the  hide  are  impregnated 
with  the  tanning  stuff.  With  regard  to  the  estimate 
of  the  difference  in  cost  and  the  durability  of  both  kinds 
of  leather,  we  believe  a  practical  calculation  will  show 
that  no  other  estimate  could  be  given  truthfully.” 


CHAPTER  CX. 

TALLOWED  OR  GRAINED  LEATHER. 

Grained  or  tallowed  cow-skins  are  those,  the  grain  of 
which  has  been  brought  out,  instead  of  being  smoothed 
down  and  polished,  as  the  sleeked  leather.  They  are 
softer  and  more  flexible  than  the  latter,  and  more  water¬ 
proof,  and  are  consequently  much  used  by  trunk-makers, 
saddlers,  and  harness-makers.  The  larger  ones  are  em¬ 
ployed  for  carriage  tops.  The  finest  cow-skins,  not  cut 
in  half,  but  entirely  dressed,  are  selected  for  the  prepara¬ 
tion  of  this  kind  of  leather.  Tread  out  the  skins  with 
the  feet  until  all  irregularities  of  surface  have  disap¬ 
peared,  then  pare  them  with  the  head-knife  to  secure 
perfect  uniformity.  The  edge  of  the  knife  should  be 
straight  and  even,  so  as  not  to  streak  or  scratch  the 
leather ;  then  dry  the  skin  partially  and  work  it  again 
with  the  foot  while  in  this  state,  and  tread  it  out  so  as 
to  free  it  from  all  depressions  of  surface. 

Dry  the  leather  partially,  beat  it  once  more,  roll  it  up 
first  upon  the  flesh,  and  afterwards  upon  the  hair  side; 


TALLOWED  OR  GRAINED  LEATHER. 


425 


the  creases  then  disappear;  if  too  hard,  moisten  it  by 
sprinkling  water  over  it.  Pommel  it  with  the  cork  from 
tail  to  head. 

Dry  th-e  leather  sufficiently  to  allow  an  insensible 
amount  of  moisture  to  remain  in  it,  flame  on  both  sides 
and  tallow  as  already  described.  Some  tanners  are  in  the 
habit,  before  this  process,  of  sprinkling  water  with  a 
brush  over  both  surfaces,  so  as  to  increase  the  pliability 
of  the  leather.  This  practice  is  improper,  as  the  excess 
of  water  prevents  the  grease  from  thoroughly  penetrat¬ 
ing  the  substance.  A  cow-skin  requires  from  three  to 
four  pounds  of  tallow,  and  a  thick  calf-skin  about  one 
pound. 

After  being  tallowed,  the  skins  are  rolled  and  left 
folded  with  the  hair  side  within  for  some  days.  They 
are  folded  square,  and  placed  to  soak  in  a  tubful  of  water 
for  eight  or  ten  hours,  and  worked  in  the  water  until  the 
excess  of  grease  is  worked  off.  The  soaking  has  been 
sufficient  when  the  surface  assumes  a  uniformly  white 
appearance. 

To  bring  out  the  grain,  the  leather  is  well  worked 
with  the  marguerite,  and  the  hair  side  is  pommelled, 
then  both  sides  are  cleaned  with  a  horse-hair  brush,  and 
the  creases  are  taken  out  from  the  parts  which  have  been 
folded,  by  the  use  of  a  smooth  stretching-iron,  the  opera¬ 
tion  being  conducted  on  a  clean  table.  Then 
the  skins  are  sprinkled  with  water,  cleaned  Fig.  139. 
again,  doubled  up  and  hung  out  to  dry,  re-  r* 

touched  with  the  stretching-iron,  and  at  last 
slightly  moistened  before  the  application  of  the  black. 

The  blacking  composition  is  prepared  and  applied  as 
for  sleeked  leather.  Then  dry  partially  the  skins,  black 
them  a  second  time,  smooth  them  with  the  stretching- 
iron,  wipe,  fold  up  with  the  hair  within,  and  pile  them 
upon  each  other.  Then  take  them  down,  blacken  a 
third  time,  smooth  and  wipe  as  before,  and  then  dry 
them  perfectly.  Then  give  them  a  coat  of  sour  beer,  and 
work  the  four  quarters  with  the  marguerite,  pommel  the 
hair  side  across,  and  rub  with  a  piece  of  old  blanket  and 
apply  a  second  coating  of  sour  beer.  When  thus  smoothed 


426 


CURRYING. 


and  cleaned,  bring  out  the  lustre  by  the  use  of  the 
stretching-iron  by  mopping  with  the  old  flannel,  and  by 
rubbing  the  surface  lightly  with  a  smooth,  compact  piece 
of  woollen  stuff,  dipped  in  the  barberry  juice.  Then 
pommel  the  surface,  at  first  obliquely,  afterwards  across 
the  breadth  of  the  skin,  and  at  last  from  tail  to  head,  so 
as  to  round  off  the  grain  as  much  as  possible. 

To  give  the  last  dressing  to  the  leather,  treat  it  again 
with  sour  beer,  expose  anew  in  the  air  until  dry,  and  rub 
once  more  with  a  cloth  dipped  in  barberry  bush  juice. 

It  takes  a  man  from  eleven  to  twelve  days  to  prepare 
completely  a  dozen  black  skins. 

Tallowed  hides  are  used  by  trunk-makers,  harness- 
makers,  and  saddlers,  and  serve  for  saddle  flaps  and  car¬ 
riage  covers,  the  largest  being  used  for  carriage  tops. 

Different  materials  are  used  to  give  a  lustre  to  skins  of 
this  kind,  as  sumach,  hot  ooze  and  water,  sour  wine,  or 
weak  brandy.  Gum  Arabic  and  sugar  dissolved  in  sour 
beer  furnish  an  admirable  liquid.  Many  other  means 
are  employed  for  the  purpose  of  giving  a  gloss  to  the 
surface,  some  consisting  of  sugar  and  molasses  dissolved 
in  beer,  others  of  infusion  of  cassia  in  beer  and  vinegar, 
etc.  All  these  substances  are  less  expensive  than  bar¬ 
berry,  and  quite  as  efficacious. 

Grain  Black.  How  to  Improve  it. — If  this  subject 
was  given  to  a  chemist  for  solution,  he  would  analyze 
the  blacking,  and  hope  by  changing  its  component  parts 
to  cause  the  desired  effect.  The  most  that  can  be  said 
for  the  best  patent  liquid  grain  which  is  now  sold  is,  that 
it  is  a  great  improvement,  both  as  to  quality  and  eco¬ 
nomy  over  the  home-made  black ,  made  from  pyrolignite 
of  iron. 

We  do  not  ignore  the  fact  that  many  curriers  of  grain 
leather  profess  to  make  a  perfect  black  which  will  stand 
on  hemlock ;  but  we  have  never  seen  such  black,  and 
think  we  should  have  seen  it  if  produced  in  this  country. 

Black ,  as  applied  to  the  coloring  of  leather,  is  a  rela¬ 
tive  term.  We  have  recently  seen  some  tanned  grain 
leather ,  i.  e.,  leather  tanned  in  salt  and  alum,  which  came 


TALLOWED  OR  GRAINED  LEATHER. 


427 


from  Japan,  which  was  so  much  blacker  than  any  black 
we  can  make,  that  ours  looks  brown  in  contrast. 

Now  if  the  curriers  of  Japan  can  thus  grain  black 
tanned  leather,  we  certainly  should  not  despair  of  grain 
blacking  all  bark  tannages. 

While  the  chemist  seeks  a  remedy  in  a  new  analysis 
of  the  blacking,  a  practical  tanner  must  seek  a  remedy 
in  the  preparation  of  the  leather. 

Our  curriers  have  little  or  no  difficulty  in  grain  black¬ 
ing  leather  tanned  in  oak  bark  or  sumach.  Why  is 
this  \  The  practical  answer  is,  that  they  hold  more  acid 
than  hemlock,  but  whatever  the  cause,  we  know  that 
the  presence  of  either  of  these  will  unite  with  or  take 
blacking  and  retain  the  color  for  a  long  period. 

In  furtherance  of  this  view  of  the  case,  we  think  it 
will  have  been  observed  by  curriers  that  hemlock  leather 
that  has  been  tanned  in  old  sour  liquors  will  take  grain 
black  much  more  readily  than  leather  tanned  in  fresh 
bark  and  liquor.  Some  leathers  have  an  old  sour  smell. 
These  leathers  of  hemlock  when  otherwise  well  prepared, 
will  be  found  to  retain  the  black  much  longer  than  the 
fresh  leather  tanned  out  mostly  by  handling  and  by  fre¬ 
quent  change  of  liquor.  If  this  is  true,  then  it  goes  to 
show  that  the  acid  in  the  hemlock  is  the  same  in  kind, 
but  not  in  quantity,  as  in  the  oak  and  sumach. 

We  must  then  remove  as  far  as  possible  the  hemlock 
tanning  from  the  grain,  and  substitute  sumach  or  oak. 
How  can  this  be  done  ? 

The  hemlock  skins  or  sides  should  be  milled  either  in 
a  wheel  or  stock,  until  the  liquor  with  which  the  leather 
was  tanned  was  removed  from  the  surface  as  far  as  possi¬ 
ble,  then  the  grain  should  be  well  scoured  on  a  table ; 
after  which  the  leather  should  be  handled  for  a  few  days 
in  a  warm  oak  or  sumach  liquor.  If  this  process  is  tho¬ 
roughly  carried  out,  hemlock  leather  may  be  made  to 
take  a  tolerably  fair  leather. 

This  is  the  process  in  use  by  most  curriers  in  Newark 
and  New  York,  who  have  the  proper  facilities,  but  un¬ 
fortunately  too  few  have  such  facilities,  and  hence  the 
miserable  attempt  to  black  grain  hemlock.  W e  have 


428 


CURRYING. 


not  noticed  the  various  methods  employed  to  kill  the 
grease,  nor  have  we  said  anything  about  the  various 
secrets  for  manufacturing  the  blacking,  as  we  assume  the 
cause  to  be  want  of  acid,  so  we  would  supply  this,  and 
that  of  a  quality  and  kind  which  is  known  not  to  injure 
the  wearing  qualities  of  the  leather.  This  done,  and 
hemlock  leather  may  be  blacked  on  the  grain  success¬ 
fully. 

But  the  harness  leather  manufacturer  says,  this  mil¬ 
ling  and  scouring  process  removes  the  weight.  This  is 
true.  But  the  old  grain  must  be  scoured  out,  and  the 
milling  or  wheeling  process  will  greatly  facilitate  this. 
Besides  the  old  grain  to  be  removed,  there  is  a  large 
amount  of  tan  liquor  and  bloom  which  must  be  removed  ; 
if  not,  the  leather  will  spew  the  oil ,  and  otherwise  make 
a  slovenly  finish. 

If  we  can  successfully  compete  with  the  French  in 
grain  blacking  calf,  colt,  and  horse  leather,  then  there  is 
no  reason  why  the  prevailing  and  very  desirable  fashion 
of  shoes  for  ladies  and  children  should  not  be  maintained. 
But  if  hemlock  leather  is  used  as  at  present,  so  imper¬ 
fectly  blacked  that  a  few  days’  wear  will  change  the 
color  to  a  foxy  hr  own,  then  we  may  expect  to  see  the 
fashion  change  as  soon  as  the  price  of  cloth  or  morocco 
shall  again  come  within  reasonable  bounds. 

Why  is  it  that  goat  morocco  does  not  thus  change 
color!  Simply  because  hemlock  tanners  have  not  ven¬ 
tured  to  lay  their  hands  upon  the  manufacture.  What 
would  be  thought  of  the  sanity  of  a  hemlock  tanner  who 
should  insist  upon  tanning  goat-skins  in  hemlock,  be¬ 
cause  forsooth  he  might  save  a  few  cents  on  each  skin, 
as  between  the  cost  of  hemlock  bark  and  sumach  1 
While  the  hemlock  tanners  would  not  think  to  venture 
on  grain  goat,  they  do  venture  and  insist  upon  tanning 
grain  calf,  and  the  result  is  what  we  all  see. 

Now  the  difference  between  the  cost  of  oak  bark  and 
hemlock  in  the  tanning  of  calf  is  so  trifling  as  hardly  to 
be  worth  mentioning,  and  yet  a  very  large  majority, 
perhaps  eight-tenths,  of  all  the  calf-skins  taken  off  in 
this  country  are  tanned  in  hemlock  bark. 


OIL  LEATHER. 


429 


The  effect  of  our  system  of  calf-skin  tanning  has  been 
to  throw  the  business  into  French  hands  of  supplying 
our  people  with  the  finer  descriptions  of  skins,  both  grain 
and  wax.  But  this  should  not  be,  and  must  not  longer 
continue. 


CHAPTER  CXI. 

WATER  LEATHER. 

The  name  of  water  leather  is  applied  to  the  larger 
and  finer  neat  skins  sent  directly  from  the  tanner  to  the 
currier,  who  does  nothing  but  pare  and  expose  them  to 
the  air  before  sending  them,  still  in  the  wet  state,  to 
the  carriage-maker.  The  latter  does  not  receive  those 
skins  until  about  to  make  use  of  them.  He  places 
them  upon  the  carriage,  fixes  them  in  position,  and 
without  making  other  changes,  blackens  and  varnishes 
them. 


CHAPTER  CXII. 

OIL  LEATHER. 

Two  kinds  of  oil  leather  are  manufactured,  one  black, 
intended  for  harness-makers,  the  other  uncolored,  for 
shoemakers’  uses.  This  leather  is  exceedingly  durable, 
and  the  most  entire  and  well-tanned  skins  are  always 
selected  for  its  preparation.  Whether  skins  are  intended 
to  be  blackened  or  not,  in  either  case  they  are  dipped, 
but  after  this  operation  has  been  gone  through,  they  are 
kept  separate,  as  the  process  is  different  for  both  kinds. 

The  kind  intended  to  be  blackened  on  the  hair  side 
should  alone  be  beaten.  The  operation  is  then  finished 
with  the  round-knife.  At  first  they  are  treated  like  tal¬ 
lowed  hides,  that  is,  dipped  and  then  beaten,  if  the 
intention  be  to  trim  them  with  the  round-knife,  and 
they  are  fleshed  if  this  is  not  the  case.  They  are  then 
worked  with  water  in  a  cask  with  a  long  pestle.  A 
number  can  be  operated  at  a  time,  and  as  the  object  is 
to  make  them  pliable  and  soft,  they  are  often  treated  in 


430 


CURRYING. 


this  way  seven  or  eight  times,  being  each  time  redipped 
and  worked  in  the  same  manner. 


After  the  skins  have  been  thus  worked,  the  flesh  side 
is  stretched  upon  marble  tables,  and  the  hair  side  worked 
with  the  stone,  and  to  extend  them  thoroughly  the 
stretching-iron  is  well  laid  on,  by  which  process  all  the 
water  is  pressed  out.  The  stone  used  for  the  purpose  is 
a  piece  of  good  grit  stone,  set  in  a  handle  in  the  same 
manner  as  the  stretching-iron.  The  skins  having  in  this 
way  been  freed  from  the  greater  portion  of  their  watery 
contents,  are  then  exposed  for  the  purpose  of  drying 
either  in  the  open  air  or  within  the  building,  one  hour’s 
exposure  usually  being  sufficient  in  summer,  while  in 
winter  many  more  are  required.  After  being  sufficiently 
dried,  they  may  at  once  be  held  in  readiness  for  the  ap¬ 
plication  of  the  oil. 

Fish  oil  is  sometimes  used  for  this  purpose,  but  it  has 
been  proved  by  experience  that  train  scouring  oil  is  the 
best  for  this  purpose.  Train  scouring  oil  is  a  mixture 
of  fish  oil  and  potash  which  has  already  served  to  clean 
skins  converted  into  chamois  leather,  and  many  advan¬ 
tages  are  obtained  by  using  it.  It  has  more  density  than 
fish  oil,  and  is  more  completely  absorbed  by  the  leather. 
Its  saponaceous  quality  contributes  to  give  softness  and 
tenacity,  and  less  of  it  is  required  than  of  oil.  Its  qual¬ 
ities  should  be  well  ascertained  before  using  it,  for  if  it 
has  not  been  well  boiled,  and  if  it  contains  water,  it  will 
not  possess  the  proper  penetrating  power. 


OIL  LEATHER. 


431 


According  to  De  La  Lande,  neat’s  foot  oil  adds  to  the 
qualities  of  the  leather.  To  obtain  it  it  is  only  necessary 
to  boil  the  foot  thoroughly  in  water,  draw  off  the  liquor 
and  place  it  in  a  kettle  with  water  to  the  boiling  point. 
Boil  this  for  twenty-four  hours;  the  pure  oil  rises  up  to 
the  top;  draw  it  and  place  it  in  another  kettle  at  about 
125°.  Let  it  remain  at  this  temperature  for  twenty-four 
hours;  cool  off.  Three  different  layers  of  oil  rise  to  the 
surface ;  draw  them  off  separately.  The  heaviest  of  these, 
according  to  De  La  Lande,  is  found  to  render  leather 
perfectly  water-proof. 

It  is  impossible  to  employ  the  scouring  alone,  whatever 
is  its  quality;  it  must  invariably  be  mixed  with  fish  oil. 
The  proportions  of  the  mixture  cannot  be  accurately 
given,  as  they  depend  upon  circumstances,  the  tempera¬ 
ture  of  the  air,  quality  of  the  leather,  dressing  intended 
to  be  given  to  it,  peculiar  mode  of  operation,  etc.  etc. 
In  summer  a  small  quantity  of  oil  is  added  to  make  the 
mixture,  while  in  winter  a  larger  quantity  is  required. 
Poor  and  thin  hides,  which  have  been  left  too  long  a 
time  in  the  lime  pits,  require  but  little  oil  and  a  good 
deal  of  scouring,  because  they  cannot  retain  much  of  the 
oleaginous  matter,  and  will  absorb  too  quickly  that  which 
has  the  greatest  penetrating  power.  When  the  skins 
are  exposed  to  the  action  of  the  mixture,  they  imbibe 
upon  the  first  application  much  more  than  upon  the 
second.  The  denser  the  scouring  oil  the  more  oil  is  re¬ 
quired,  but  the  quantity  of  the  latter  which  is  often 
made  to  amount  to  one-quarter  of  the  mixture,  should 
never  exceed  one-half  of  it. 

Experience  has  shown  that  for  a  neat-skin  weighing 
from  15  to  16  lbs.,  4  lbs.  of  oil  material  are  required, 
and  that  10  lbs.  are  expended  upon  a  dozen  calf-skins 
weighing  28  lbs.,  thus  giving  the  proportion  of  about 
one-quarter  of  their  weight  of  oil  for  the  former,  and 
one-third  for  the  latter. 

Skins  intended  to  be  oiled  should  contain  just  enough 
water  to  enable  them  to  yield  a  small  quantity  upon 
being  wrung  out.  If  they  be.  dry  or  slightly  moist,  they 
will  absorb  the  oil  too  rapidly,  while  it  is  essential  that 


432 


CURRYING. 


their  substance  be  gradually  penetrated  by  it.  When 
they  are  too  wet  they  take  it  up  slowly  in  proportion  as 
they  lose  their  water.  Therefore  before  oiling  them  the 
operator  should  carefully  ascertain  that  they  are  just  wet 
enough  for  this  purpose,  and  should  moisten  again  those 
parts  which  have  become  too  dry.  The.  other  extreme 
should  be  as  carefully  guarded  against,  because  when 
the  hides  are  too  wet,  too  much  of  the  scouring  oil  is 
consumed  in  forming  a  soapy  compound  with  the  water. 

After  the  skins  have  been  oiled  on  both  sides,  and  the 
workman  has  uniformly  distributed  the  oil  over  the  sur¬ 
faces  with  the  hand  or  the  tallowing  cloth,  he  hangs  them 
up  by  the  hind  quarters  and  allows  them  to  remain  in 
the  air  long  enough  to  absorb  their  contents  of  oil. 
taking  care  not  to  let  them  be  exposed  to  the  extreme 
heat  of  the  sun,  or  to  a  great  draught  of  air,  as.  if  they 
be  dried  too  rapidly,  the  oil  will  not  penetrate  them 
gradually.  Ten  or  twelve  hours  of  exposure  are  suffi¬ 
cient  in  summer,  while  in  winter  it  requires  two  or  three 
days.  The  bellies  of  neat  hides  require  less  oil  than  the 
other  parts,  while  on  the  contrary  those  of  calf-skin 
absorb  more. 

There  is  no  uniform  method  for  oiling  skins.  In  some 
establishments  the  oil  alone  is  applied  to  the  hair  side, 
while  a  mixture  of  oil  and  scouring  is  placed  on  the  flesh 
side;  in  others  the  mixture  is  applied  to  both  surfaces. 
Again  some  curriers  make  use  of  no  oil  whatever,  but 
apply  the  scouring  oil  to  both  sides,  taking  care  only  to 
stuff  the  flesh  side  most  plentifully  with  it.  These  differ¬ 
ent  modes  appear  to  succeed  equally  well, 'and  we  refrain 
from  condemning  any  of  them,  but  we  must  observe  that 
care  should  be  taken  not  to  give  the  hair  side  too  great 
an  amount  of  scouring,  or  it  will  be  very  difficult  to  give 
a  gloss  to  the  surface.  Skins  intended  for  saddlers 
require  by  one-third  less  of  oil  stuffing  than  is  needed  for 
shoemaker’s  leather. 

After  the  skins  have  become  sufficiently  dry,  they  are 
fulled  and  recharged  with  some  fish  oil  and  a  lesser 
quantity  of  scouring  oil,  again  fulled,  and  at  last  the  hair 
side  is  to  be  thoroughly  scoured  by  a  brush  dipped  in  a 


OIL  LEATHER. 


433 


lye  of  potash.  Immediately  after  this  the  skins  are 
blackened,  care  being  taken  to  keep  the  borders  clean. 
The  blacking  has  already  been  described,  and  is  applied 
in  the  same  manner.  After  the  first  blacking,  pommel 
the  skins  crosswise,  apply  a  second  coating  of  black,  and 
expose  them  to  the  air  until  completely  dry.  Then  beat, 
pommel,  and  trim  them,  pass  over  with  the  head  of  the 
round-knife,  rub  with  the  cork,  and  terminate  the  process 
by  lightly  rubbing  the  hair  side. 

These  last  operations  are  differently  performed  by 
different  curriers.  Some,  after  the  first  coating  of  black, 
do  not  full  the  skins,  but  stretch  them  with  the  stretch¬ 
ing-iron  upon  the  table.  They  moisten  the  hair  side, 
pass  over  it  the  solution  of  potash,  and  give  a  second 
coat  of  blacking.  To  smooth  and  to  impart  grain  they 
pommel  them  from  tail  to  head,  and  across  the  grain. 
This  last  method  is  preferable. 

As  harness-makers  need  for  their  purposes  very  strong 
skins,  square  oiled  hides  are  prepared  especially  for 
them,  or  skins  the  head  and  belly  pieces  of  which  have 
been  cut  off,  by  which  each  skin  is  reduced  to  4|  feet  in 
length,  and  about  three  feet  in  breadth.  The  following 
figure  represents  a  square  oiled  hide  or  croupon. 


Fig.  142. 


Oiled  Leather. — We  class  under  this  head  a  kind  of 
leather  prepared  without  tannin  or  alumina,  and  having 
the  grain  surface  of  the  skin  removed.  Fish  oil  is  the 
principal  substance  employed,  and  has  no  chemical  action 
on  the  tissue.  The  skins  imbibe  the  oil  by  mechanical 
force,  which  expels  the  moisture  and  with  it  all  putres¬ 
cent  matters  soluble  in  cold  water.  This  leather  is  com¬ 
monly  known  by  the  name  of  Chamois ,  because  it  was 
28 


434 


CURRYING. 


originally  made  from  the  skin  of  the  wild  animal  of  that 
name.  It  is  also  called  Lash  leather.  Its  use  is  now 
almost  exclusively  limited  to  domestic  purposes,  being 
employed  chiefly  for  washing  and  polishing  furniture. 

The  preliminary  operations  are  the  same  as  for  tan¬ 
ning,  and  the  process  can  be  applied  to  goat,  sheep, 
lamb,  deer,  etc.,  skins,  care  being  taken  to  choose  the 
finest  add  most  perfect. 

The  skins  are  brought  to  the  state  of  Pelt  by  washing, 
liming,  fleecing,  beaming,  and  branning  in  the  same 
manner  as  for  kid  leather;  they  are  subjected  to  the 
frizzing  operation,  which  is  rubbing  them  with  pumice 
stone,  or  working  them  under  the  round  edge  of  a  blunt 
knife.  This  operation  removes  the  grain  surface ,  equal¬ 
izes  the  thickness  of  the  skin,  renders  it  pliable,  and 
exposes  a  softer  surface. 

Wring  out  the  skins  and  transfer  them  to  the  trough 
of  a  fulling  mill,  and  subject  them  to  the  continuous 


Fig.  143. 


action  of  the  wooden  hammer  until  nearly  dry,  then  re¬ 
move  them,  spread  them  upon  the  table,  and  sprinkle 
them  over  the  surface  with  fish  oil.  Fold  them  in  bun¬ 
dles  of  four,  and  return  them  to  the  trough  and  beat 


WAXED  LEATHER. 


435 


them  as  before  from  two  to  four  hours,  as  may  be  neces¬ 
sary  to  produce  a  perfect  impregnation  with  the  oil,  after 
which  take  them  out  again,  open,  expose  them  to  the  air 
for  a  short  time,  and  then  besmear  them  with  grease 
and  full  as  before.  Repeat  these  manipulations  eight  or 
ten  times,  until  the  skin  becomes  thoroughly  impreg¬ 
nated  with  oil.  One  gross  of  skins  requires  from  three 
to  five  gallons  of  oil. 

After  the  oil  has  been  well  beaten  into  the  pores,  and 
there  is  no  appearance  of  greasiness,  take  the  skins  out 
and  suspend  them  by  hooks,  to  wooden  hangers  running 
across  a  drying  chamber,  about  six  feet  high  and  twrelve 
feet  square,  heated  by  steam  pipes.  This  treatment 
causes  a  slight  fermentation,  which  dilates  the  pores, 
and  promotes  the  intimate  incorporation  of  the  oil  with 
the  animal  fibre. 

Remove  the  excess  of  oil  by  immersing  and  handling 
the  skins  for  one  hour,  in  slightly  heated  potash  lye  at 
2°  Beaume,  which  converts  it  into  a  soluble  soap.  Wring 
them  at  the  peg,  dry,  finish  at  first  on  the  stretcher, 
and  smooth  at  last  with  rollers.  To  give  them  a  buff 
color,  dip  them  merely  in  an  infusion  of  oak  bark,  which 
in  this  case  is  used  as  a  dye. 

The  fulling  mill  consists  of  two  stocks,  the  head  co¬ 
vered  with  copper,  being  attached  to  a  long  beam  or 
handle  lying  in  an  inclined  position.  Near  the  lower 
end  of  each  a  wheel  revolves,  by  which  each  hammer  is 
raised  and  dropped  through  a  space  of  about  a  foot  into 
the  trough  beneath.  The  upper  or  handle  end  of  each 
stock  is  adjusted  so  as  to  work  on  pivot  or  axis^and  the 
stocks  being  set  in  action  the  two  descend  and  rise 
alternately,  and  beat  the  skins  uniformly  until  perfectly 
dry. 


CHAPTER  CXIII. 

WAXED  LEATHER. 

Waxed  skins  are  those  which  have  been  rubbed  over 
with  melted  wax,  and  maintained  at  a  heat  sufficiently 
great  to  allow  it  to  penetrate  the  leather.  This  mode 


436 


CURRYING. 


being  costly  very  few  are  now  prepared,  principally  as 
saddlers  and  harness-makers  no  longer  buy  them.  The 
name  is  now,  however,  applied  almost  entirely  to  tallow 
hides  which  h^ve  originally  had  great  consistency,  being 
very  carefully  prepared.  Some  curriers,  to  give  great 
firmness  to  certain  skins,  add  to  the  tallow  from  one- 
eighth  to  one-quarter  of  wax.  Generally  smooth,  sleek 
skins,  with  this  property  of  great  firmness,  are  used  and 
sold  by  carriage- makers  as  waxed  skins,  and  are  held  in 
great  esteem  for  their  beauty  and  durability. 


CHAPTER  CXI V. 

ENGLISH  HIDES. 

These  skins  are  so  called  which  are  made  pliable  by 
means  of  tallow,  and  retain  their  reddish  or  yellowish 
color.  They  select  for  this  purpose  tanned  skins  of  the 
best  quality,  white  on  the  hair  side,  clean,  and  free  from 
greenness.  They  are  dipped  in  the  same  manner  as 
sleeked  leather,  and  are  carefully  handled,  as  the  least 
spot  renders  them  unfit  for  use.  After  having  been 
dipped  and  exposed  to  the  air,  they  are  then  worked  and 
pared,  and  are  well  pommelled  on  both  sides  to  efface 
the  wrinkles ;  they  are  thoroughly  dried  before  being 
tallowed. 

When  done,  wet  the  hair  side  with  a  clean  cloth  dipped 
in  pure  water,  so  as  to  prevent  tallow  entering  the  weak 
parts.  The  tallow  applied  to  the  flesh  side  should  not 
be  as  warm  as  that  used  for  the  tallow  hides  and  sleeked 
leather,  and  as  the  principal  object  of  the  process  is  to 
make  them  retain  their  natural  color,  only  a  small  quan¬ 
tity  should  be  applied,  so  that  it  shall  not  fully  penetrate 
to  the  hair  side.  The  skins  are  soaked  half  an  hour  in 
clean  water  after  they  have  been  tallowed.  The  process 
is  thus  described  :  “  After  the  skins  have  been  soaked, 

they  should  be  worked  in  water,  and  a  light  and  uniform 
coating  of  fish  oil,  or  what  is  better,  linseed  oil,  is  spread 
over  the  hair  side  with  a  piece  of  wool  or  cloth.  Then 
they  are  dried,  and  the  process  is  finished  as  for  sleeked 


ENGLISH  HIDES. 


431 


leather,  except  that  a  stretching  tool  of  copper  is  used 
instead  of  iron,  which  might  spoil  the  surface.  Dry 
thoroughly  the  skin,  and  apply  on  the  hair  side  a  color 
made  of  French  berries.  One-half  a  drachm  of  berries 
dissolved  in  one  quart  of  beer  is  sufficient  to  color  six 
hides.  The  color  is  laid  on  carefully  so  as  to  secure  an 
uniform  coating,  and  as  briskly  as  possible,  otherwise  the 
skin  will  be  spotted  or  discolored. 

“  After  the  skins  are  colored,  dry  them  in  the  open 
air  in  the  shade,  because,  if  exposed  to  the  heat  of  the 
sun  it  will  cause  the  oily  matter  to  penetrate  through  to 
the  hair  side  and  discolor  its  surface.  The  barberry  is 
not  required,  but  it  is  sufficient  to  rub  the  skin  until  it 
becomes  dry  with  a  small  cloth  or  piece  of  linen,  by 
which  the  surface  is  rendered  sufficiently  smooth  and 
polished.  Some  do  not  even  color  skins  of  this  kind, 
content  themselves  with  smoothing  them. 

“  Another  different  method  is  sometimes  followed. 
When  the  skins  meant  to  be  yellowed  have  been  pre¬ 
pared,  pommel  them  to  make  the  inequalities  of  the 
surface  disappear*  and  full  them  in  a  cask  containing 


Fig.  144. 


clean  water.  Place  thefh  then  upon  a  marble  table,  with 
the  flesh  side  uppermost ;  replace  again  upon  the  stone 
with  the  hair  side  up  for  staining,  and  drawn  out  with 
the  stretching-iron.  This  should  be  pressed  down  very 
firmly,  for  the  purpose  of  stretching  the  leather  and  of 
making  it  compact  and  firm.  Then  dry  them  a  little, 
and  again  and  again  treat  them  with  the  stretcher  of 


438 


CURRYING. 


copper,  care  being  taken  to  dry  them  well  after  each 
dressing  with  a  clean  woollen  cloth.  After  this  apply 
linseed  oil  to  the  hair  side  ;  and  a  composition  of  equal 
parts  of  fish  oil,  scouring  oil,  and  fine  white  tallow 
melted  together  and  passed  through  a  hair-cloth  sieve, 
is  used  for  the  flesh-side.” 

In  order  that  the  shoulders  and  legs  should  have  a 
uniform  color  with  the  body,  it  is  proper  to  apply  a  less 
amount  of  liquid  to  them.  After  this  oiling,  the  skins 
are  dried  by  hanging  them  upon  a  rod  with  its  ends 
passed  through  the  tail  and  one  of  the  legs.  When  dry 
they  are  placed  anew  upon  a  marble  table,  the  flesh  side 
is  stretched  out  with  a  warm  stretching  iron,  for  the  pur¬ 
pose  of  cleaning  them  and  making  them  compact.  The 
hair  side  is  then  placed  upwards,  moistened  with  a  little 
clear  water,  treated  with  the  copper  stretcher,  dried  care¬ 
fully  with  a  clean  rag,  and  passed  over  with  the  stretcher 
once  more  before  the  final  drying.  Sometimes  they  use 
a  color  made  with  a  little  Brazil  wood,  Yellow  berries, 
and  glue  heated  together.  This  color  is  passed  rapidly 
and  lightly  upon  the  hair  side,  and  the  leather  is  then 
stretched  and  exposed  to  the  air  until  perfectly  dry,  and 
is  finally  sleeked  with  a  piece  of  glass  attached  to  a  handle 
like  that  of  a  stretching-iron.  Skins  thus  prepared  are 
higher  priced  than  tallowed  leather,  and  are  chiefly  used 
by  harness-makers. 


CHAPTER  CXV. 

WHITE  LEATHER  AND  COMMON  RUSSET. 

White  Leather  is  used  principally  by  shoemakers  for 
the  uppers  of  large  shoes,  the  hair  side  being  placed 
within.  The  skins  are  not  worked  up  whole,  but  are 
made  into  square  hides  by  cutting  up  the  heads  and  belly 
pieces  which,  being  too  thin  for  the  purpose  for  which  the 
leather  is  employed,  are  used  for  the  first  or  upper  soles. 

Dip  the  skins  well  at  first  and  scrape  them  carefully 
with  the  head-knife  without  being  shaved.  Then  treat 
both  sides  with  oil  and  train  oil  scourings,  dry,  beat  out 


CURRYING  OF  CALF-SKINS. 


439 


with  the  feet,  trim  on  the  borders,  press  and  pommel 
them  to  efface  the  creases.  Complete  the  preparation  by 
pommelling  with  the  cork,  so  as  to  smooth  the  flesh  and 
grain  the  hair  side. 

This  leather  is  well  stuffed,  each  skin  absorbing  usually 
3-j;  lbs.  of  oil  and  train  scouring  oil.  Some  curriers  pom¬ 
mel  only  these  skins  on  both  sides,  and  dry  them.  They 
assert  that  they  are  finer  than  when  beaten. 

Common  Russet  is  prepared  as  blackened  leather,  ex¬ 
cept  it  is  allowed  to  absorb  grease  to  saturation,  so  as  to 
increase  its  strength  and  pliability.  For  this  purpose, 
after  the  skins  have  been  tallowed  and  partially  dry, 
they  are  saturated  with  train  oil  scourings  on  each  side, 
about  i\  lb.  being  used  for  each  skin.  This  leather 
preserves  nearly  its  original  color, «and  is  used  principally 
for  pump-valves,  mail-bags,  etc.  etc. 


CHAPTER  CXVI. 

CURRYING  OF  CALF-SKINS.— OILED  CALF-SKINS. 

Calf-skins  are  sometimes  prepared  in  the  same  man¬ 
ner  as  neat’s  leather,  the  thickest  and  largest  of  them 
being  used  for  the  same  purpose  as  square  hides ;  but 
the  latter  being  commonly  employed  in  the  manufacture 
of  soles,  the  calf-skin  leather  being  only  used  for  uppers, 
and  being  consequently  required  to  possess  more  plia¬ 
bility  and  softness,  must  be  treated  by  processes  differing 
from  those  to  which  thick  leather  is  subjected. 

Oiled  Calf-skins. — As  soon  as  the  skins  are  taken  from 
the  pit,  dry  them  immediately,  scrape  and  tread  them 
out  under  the  feet,  and  then  oil  on  both  sides.  In  win¬ 
ter  you  can  use  warm  oil.  As  for  cow-skins,  use  a  mix¬ 
ture  of  equal  parts  of  oil  and  scouring  train  oil.  If  the 
train  oil  is  very  clear,  it  can  be  used  alone.  A  dozen  of 
calf-skins  weighing  from  30  to  36  lbs.  generally  require 
from  10  to  12  lbs.,  though  experience  alone  can  guide 
the  workman  to  judge  the  amount  the  skins  will  absorb 
without  injury.  Avoid  the  use  of  an  excess  of  fatty 
matter,  as  it  tends  to  make  the  leather  too  soft  and 


440 


CURRYING. 


flabby.  If  the  skins  have  been  exposed  too  long  in  the 
lime,  they  do  not  take  up  as  much  oil  as  those  which 
have  not  been  thus  injured.  After  the  oiling,  dry  the 
skins  and  dress  and  soften  them  by  beating  them  with 
the  feet,  and  bring  the  grain  in  the  usual  manner.  If 
the  skin  is  intended  to  be  waxed,  or  converted  into 
grained  or  stamped  leather,  they  do  not  require  to  be 
worked  with  the  feet. 

In  order  to  cleanse  and  soften  the  leather  and  prepare 
it  to  receive  the  black,  dip  a  brush  in  a  solution  of  pot¬ 
ash,  made  by  dissolving  about  one  pound  of  potash  in  a 
bucketful  of  water,  and  pass  it  over  the  hair  side.  If 
the  solution  is  stronger  it  injures  the  leather,  but  the 
above  is  sufficient  to  saturate  the  excess  of  oil  and  enable 
the  black  to  adhere  more  readily  to  the  surface.  When 
this  operation  is  completed,  apply  at  once  the  liquid 
blacking  as  above,  being  careful  to  not  lay  on  a  large 
enough  quantity  to  penetrate  below  the  surface  of  the 
leather. 

Pommel  the  skins  then  from  head  to  tail  with  a  me¬ 
dium  sized  pommel ;  use  four  parts  of  oil  and  one  of 
scouring  train  oil  to  smooth  down  the  long  ridges  which 
traverse  the  leather  in  different  directions. 

Apply  then  a  second  coat  of  black,  and,  if  necessary, 
charge  again  the  leather  with  the  oily  mixture,  and  dry 
thoroughly  in  the  air.  Then  tread  it  out,  pommel  on 
both  sides,  pare  down  on  the  borders  with  the  head- 
knife  and  scrape  with  the  round-knife.  To  complete  the 
preparation,  pommel  with  the  cork,  and  rub  lightly  over 
the  grain  with  fish  oil  to  deepen  the  color,  which  would 
have  been  injured  by  the  previous  operations. 

Sometimes  curriers  follow  another  method.  After  the 
skins  are  dried  and  oiled,  they  soak  them  in  a  tub  until 
sufficiently  damp,  while  they  are  not  thoroughly  pene¬ 
trated  through.  They  are  then  pommelled  lengthwise 
and  blackened.  Then  they  are  pommelled  crosswise, 
blackened  a  second  time,  charged  with  the  oily  mixture, 
thoroughly  dried,  worked  with  the  pommel  from  head  to 
tail,  and  oiled  as  before. 


ENGLISH  CALF-SKINS. 


441 


CHAPTER  CXVII. 

TALLOWED  CALF-SKINS. 

A  large  proportion  of  the  calf-skins  used  are  oiled, 
but  those  which  are  tallowed  are  less  liable  to  be  pene¬ 
trated  by  moisture.  To  prepare  them,  sprinkle  the  dry 
skins  with  water,  scrape  them  with  a  dull  knife  or  the 
stretching-iron,  unless  it  is  desirable  to  diminish  their 
thickness  by  paring.  Then  pare  down  the  head  with 
the  head-knife  as  far  as  the  junction  of  the  neck,  flesh 
the  body  lightly,  being  careful  to  moisten  the  surface  to 
prevent  the  knife  entering  too  deeply.  Dry  the  skins, 
and  pommel  them  upon  the  flesh  side  with  a  large  pom¬ 
mel,  and  upon  the  grain  with  the  cork  instead  of  pumice 
stone.  Tallow  in  the  same  manner  as  cow-skins,  dry, 
then  work  under  water,  pommel  and  blacken  twice  ; 
after  this  operation  pommel  again,  polish  and  rub  upon 
the  grain  side  with  clear  oil.  A  dozen  of  calf-skins 
weighing  from  38  to  40  lbs.  require  from  12  to  15  lbs. 
of  tallow. 

Harness-makers  and  saddlers  use  these  skins  for  co¬ 
vering  horse-collars,  and  for  other  purposes.  They  are 
also  used  for  manufacturing  thick  shoes,  and  to  cover 
trunks,  chairs,  and  table. 


CHAPTER  CXVIII. 

ENGLISH  CALF-SKINS. 

To  prepare  this  kind  of  leather,  choose  the  best  kind 
of  skins,  and  the  process  of  manufacturing  is  similar  to 
that  employed  for  cow-skins  intended  for  corresponding 
purposes. 

Tallow  the  skins  upon  the  flesh  side,  but  use  only  a 
small  quantity  of  grease,  so  as  not  to  penetrate  the  leather. 
This  and  the  succeeding  operations  must  be  very  care¬ 
fully  conducted,  to  avoid  injuring  or  soiling  the  surface. 

The  thinner  skins  are  used  for  thin  soles,  while  the 


442 


CURRYING. 


thicker  ones  are  curried  white  for  the  uppers  of  thick 
shoes.  Formerly  this  white  leather  was  used  for  heel- 
vangs.  Moisten  the  skins  slightly,  pommel  them  in  every 
direction,  and  after  oiling  and  thoroughly  cleaning,  shave 
them  down  on  the  borders,  pare  from  tail  to  head  until 
soft,  then  pommel  and  scrape  them  with  the  round- 
knife,  and  pass  over  with  the  cork.  During  all  these 
operations  avoid  scraping  or  scratching  the  surfaces, 
which  are  more  liable  to  be  injured  than  those  of  neat’s 
leather.  If  the  skins  come  from  still-born  calves,  you 
avoid  injuring  them  by  passing  them  through  tan  liquor 
and  exposing  them  for  a  time  in  the  pits. 


CHAPTER  CXIX. 

WAXED  CALF-SKINS* 

Fleshing  and  Shaving. — In  a  preceding  chapter  we 
have  given  the  best  process  for  tanning  calf-skins;  we 
now  give  a  description  of  the  different  processes  to  which 
the  currier  submits  such  tanned  skins. 

Good  dressers  of  waxed  calf-skins  have  become  in  our 
day  very  rare.  For  about  twenty  years  past  the  manu¬ 
facturers  of  patent  leather  have  appropriated  all  the  good 
workmen  and  have  kept  them  busy,  and  since  more  is 
earned  on  patent  leather  than  in  dressing  waxed  calf¬ 
skins,  the  currier  is  almost  the  only  workman  left  who 
carries  his  work  mechanically  and  without  principle. 

The  English  taught  us  to  dress  the  skins  which  we 
understood  how  to  tan  better  than  they.  We  have  ex¬ 
celled  them,  and  now  they  are  tributary  to  us,  thanks  to 
the  improvements  which  we  have  made  upon  their  les¬ 
sons.  The  Germans  do  as  well  with  their  glazed  leather 
and  dressing  hides  as  we  do,  but  in  the  manufacture  of 
sole  leather,  waxed  calf-skins,  boot  legs,  and  saddle  leather 
we  are  far  beyond  them. 

*  This  process  of  manufacturing  waxed  calf-skins  is  extracted  from 
“La  Halle  aux  cuirs,”  Paris,  1864,  and  is  the  work  of  M.  Rene,  one 
of  the  best  Parisian  curriers. 


WAXED  CALF-SKINS. 


443 


For  the  first  process  use  the  plate  knife,  and  to  sharpen 
it  proceed  as  follows:  For  this  purpose  use  the  finest 
sandstone,  which  is  long  and  round,  and  hold  the  knife 
turned  to  the  back  and  inclined  about  two-thirds;  to 
begin  press  upon  it  hard,  taking  care  to  turn  the  sand¬ 
stone  every  two  or  three  minutes  in  order  to  keep  it  even, 
which  is  essential  in  order  to  have  the  edge  of  the  blade 
remain  exactly  regular.  As  soon  as  you  reach  an  edge, 
assure  yourself  of  it  by  holding  it  up  to  the  light,  when 
you  notice  a  light  feather  which  follows  the  whole  length 
of  the  edge.  Continue  with  the  sandstone,  but  do  not 
press  hard,  the  mere  weight  of  the  hand  and  blade  being 
sufficient.  Then  make  two  or  three  strokes  upon  the 
other  side,  and  in  five  -minutes  the  feather  vanishes. 
When  the  edge  upon  the  sandstone  is  gained,  take  the 
Scotch  stone,  which  is  the  best  of  all  the  stones.  It  is 
an  eight-cornered  stone  with  a  very  sharp  grain,  and 
with  it  the  edge  can  be  burnished  in  ten  minutes.  The 
action  upon  this  stone  shows  a  new  feather  almost  imper¬ 
ceptible  to  the  eye,  but  you  can  feel  it  very  plainly  if 
you  let  your  finger  nail  glide  along  the  edge.  This  is 
removed  in  the  same  way  as  that  which  first  appeared 
upon  the  sand-stone,  take  care,  however,  to  carry  the 
knife  lighter.  When  the  feather  has  disappeared  the 
edge  feels  smoother,  and  then  you  take  the  whetstone 
and  proceed  as  before.  In  a  very  little  while  you  obtain 
a  smooth  edge,  and  if,  when  you  run  your  nail  along 
upon  it,  you  feel  its  sharpness,  and  the  nail  meets  no 
resistance,  the  edge  is  ready  and  can  now  be  turned. 

In  this  operation  proceed  in  the  following  manner: 
Cover  the  edge  with  tallow,  take  the  plate  of  steel  which 
must  be  carefully  polished,  and  let  yourself  down  upon 
your  knees.  Take  the  cross  handle  between  your  legs, 
incline  the  knife  to  the  right,  and  bring  the  steel  to  the 
edge;  give  the  first  stroke  to  the  right,  turn  the  knee 
slightly  and  give  a  second  stroke,  giving  lighter  strokes 
as  you  proceed,  you  come  to  the  edge  which  turns  under 
the  pressure.  You  rest  no  longer  upon  the  end  than 
upon  the  middle  to  obtain  a  uniform  edge,  and  if  when 
you  press  the  knees  together  you  have  raised  the  knife 


444 


CURRYING. 


nearly  perpendicular,  you  stop,  for  if  you  went  on,  you 
would  fall  and  break  out  the  edge,  a  fault  of  which  many 
workmen  are  guilty. 

In  order  to  flesh  and  shave  calf-skins,  it  is  necessary 
that  the  edge  should  remain  a  little  open,  and  especially 
that  it  is  not  set  too  strong,  for  it  is  better  to  take  off 
two  shavings  than  one.  The  workmen  who  work  with 
their  edges  set  too  strong,  shave  almost  all  their  skins 
too  hard,  and  when  they  come  to  the  sides  they  often 
press  deep  into  the  leather.  We  have  often  seen  how 
unmercifully  skins  were  handled  in  this  way,  and  ob¬ 
served  also  that  workmen  of  this  kind  work  with  too 
open  a  grade  and  penetrate  the  skin  against  their  will. 
A  middling  edge,  not  too  open,  is  the  best. 

Use  the  English  beam,  the  surface  of  which  is  always 
very  even  lengthwise.  Of  this  one  must  assure  himself 
by  using  a  very  exact  straight  edge,  for  the  least  hollow, 
the  smallest  bunch,  must  be  removed.  Then  look  to 
breadth  in  the  same  way,  and  see  whether  it  is  exact. 
This  you  ascertain  by  laying  the  back  of  the  knife  upon 
it.  Move  it  up  and  down  and  observe  whether  it  meets 
with  any  obstacle.  The  currying  board  must  be  rounded 
quite  lightly  and  even  at  the  edges.  The  thinner  a  skin 
is  the  evener  must  be  the  surface  of  the  beam.  The 
upright  frame  of  the  beam  must  be  inclined  towards 
the  side  of  the  workman  at  least  two  inches. 

After  the  instrument  is  well  ground  and  set,  and  the 
board  well  prepared,  proceed  to  flesh  the  calf-skin ;  and 
that  the  knife  may  not  suffer  by  bits  of  tan  if  such  should 
remain  sticking  in  the  flesh  side,  have  the  skin  well 
brushed  upon  the  flesh  and  grain.  Then  take  the  skin 
and  lay  it  crosswise  upon  the  beam,  a  ravel  in  each  hand, 
the  tail  piece  toward  you  and  the  breast  part  hanging 
down.  Begin  upon  the  right  side  of  the  skin,  give  it  a 
light  blow  with  the  sharpening  steel  to  press  it  down, 
drive  the  knife  into  the  flesh  at  the  navel,  and  go  down 
over  it  to  the  end  of  the  breast  points.  Cleave  only  the 
flesh  and  preserve  the  membrane  upon  the  skin  every¬ 
where.  Bring  the  skin  from  left  to  right,  and  give  the 
second  stroke.  Go  down  as  far  as  the  arm  will  reach,  in 


WAXED  CALF-SKINS. 


445 


such  a  way  as  to  cleave  the  flesh  only,  without  cutting 
into  the  skin.  When  you  come  to  the  back  lines,  and 
especially  to  the  skin  at  the  back  of  the  neck,  take  good 
care  to  have  the  knife  sharp,  for  since  there  is  a  stronger 
membrane  in  the  lines  of  the  back  than  in  other  parts, 
you  might  go  in  too  deep  and  make  a  hole  like  an  egg. 
We  often  see  in  the  middle  of  a  handsome  calf-skin  a 
defect  like  this,  caused  by  an  awkward  workman.  Go 
on  with  the  work  from  left  to  right.  Spread  out  the 
skin  over  the  upper  corners  of  the  beam  with  great  care, 
and  hold  it  fast  with  the  knees,  so  that  it  cannot  move 
from  its  place  in  one  direction  or  another,  for  the  least 
displacement  often  damages  the  skin. 

When  you  have  done  here,  turn  the  skin  from  right 
to  left,  and  begin  the  work  again  at  the  right  fore-leg. 
Move  this  twice  in  order  to  get  around  the  joints,  and 
to  sever  the  nerves  of  the  shank,  which,  since  it  is  * 
stronger  than  that  of  the  sides,  may  make  you  commit 
a  like  fault  to  that  mentioned  above.  Proceed  with  all 
possible  caution  to  flesh  the  neck  lengthwise,  taking 
care  to  press  sharply  against  the  knife,  and  draw,  or 
rather  mow,  the  flesh  off,  but  rest  upon  the  knife  only 
lightly.  When  you  come  to  the  breast  or  to  the  head, 
press  on  more  in  the  stroke,  but  take  only  the  flesh,  and 
take  no  particular  care  to  leave  the  skin  smooth ;  this 
matter  is  attended  to  in  finishing. 

When  the  calf-skin  is  well  fleshed  upon  the  neck  and 
breast,  turn  it  back  to  its  former  position,  and  treat  the 
tail  part  in  the  same  style.  In  this  way  you  finish  the 
skin  in  three  operations.  Avoid  forcing  the  strokes  on 
the  tail  part,  and  everywhere  mow  off  the  flesh,  and 
never  double  the  stroke.  By  means  of  a  little  piece  of 
steel  preserve  the  sharpness  and  set  of  the  blade. 

When  the  calf-skins  are  fleshed,  hand  them  over  to 
the  grainer,  who  breaks  the  vein,  stretches  the  skin  out, 
works  them,  in  a  word,  gives  them  the  grain.  This 
process  is  useful,  and  it  can  be  made  up  for  by  nothing 
else  :  a  calf-skin  cannot  be  curried  to  perfection  if  it  is 
not  first  grained  with  the  grainer’s  wood. 

When  the  calf-skin  is  grained,  take  it  again  to  the 


446 


CURRYING. 


beam,  and  even  off  the  throats  and  the  cheeks.  Feel 
carefully  through  them  first  so  as  not  to  make  useless 
strokes  in  the  same  direction,  and  these  strokes  must 
cross  each  other  in  order  to  even  off  the  head  part  well. 
When  the  head  and  breast  are  well  evened,  the  object 
is  accomplished.  Fold  the  skin  once  and  go  over  quite 
lightly  with  the  shaving  knife.  For  this  purpose  the 
back  must  be  up.  The  cut  goes  straight,  and  do  not 
rest  or  press  upon  the  beam  with  the  knife.  It  must  be 
carried  down  quite  naturally,  but  with  a  sure  hand, 
taking  off  the  rest  of  the  flesh  and  bringing  with  it  the 
bunches  of  flesh.  We  do  not,  however,  approve  of  a 
style  of  finishing  which  takes  off  a  great  shaving,  for  by 
this  the  skin  loses  in  weight.  On  this  account  have  the 
calf-skin  shaved  over  crosswise,  very  lightly  only,  but 
should  it  be  necessary  to  manufacture  them  to  sell  by 
the  dozen,  take  off  all  the  thick  places,  off  the  fore¬ 
shanks  and  the  joints  uniformly,  take  off  one  or  two 
membranes  from  the  sides,  and  also  from  the  tail ;  in  a 
word,  you  must  use  shoulder  power,  as  one  must  if  he 
will  really  complete  his  work.  But  we  repeat  that 
selling  by  weight  has  debased  the  hand  of  the  workman, 
and  he  is  compelled  to  go  over  a  calf-skin  very  lightly 
to  preserve  the  weight.  Hence  you  shave  the  skin  on 
both  sides,  then  repeat  the  stroke  on  a  quarter  of  a  back. 
Everywhere  the  veins  are  shaved  through  a  second  time; 
the  shoulder  piece  retains  its  strength,  the  extremities 
are  spared,  not  the  least  unevenness  nor  the  smallest  cut 
is  perceptible,  and  the  calf-skin  is  curried  as  the  neces¬ 
sities  of  the  trade  require. 

Before  passing  over  to  the  process  which  is  now  fol¬ 
lowed,  we  shall  make  a  few  remarks  in  reference  to  cur¬ 
rying.  In  the  majority  of  manufactories  calf-skins  are 
now  no  longer  shaved  transversely,  but  only  lengthwise, 
and  indeed  it  is  done  to  save  a  few  cents.  In  our  opinion 
it  is  better  to  spend  on  a  skin  a  little  more  and  have  it 
completely  finished. 

We  proceed  now  to  the  finishing,  which  is  called  by 
the  trade  the  setting  out,  or  the  settling  to  the  wind. 
This  process  is  the  most  important  of  all  table  work,  and 


WAXED  CALF-SKINS. 


447 


it  is  likewise  the  most  neglected,  for  routine  hns  taken 
the  place  of  the  knowledge  of  our  first  teachers. 

In  finishing,  bring  the  shaved  calf-skins  together  in  a 
tub  with  weak  liquor,  if  you  have  any  ready,  or  in  clean, 
pure  water.  It  is  well,  if  there  is  time,  to  have  them 
rinsed  in  this  water  at  least  24  hours ;  then  they  are 
taken  out  and  laid  with  sides  turned  in,  rolled  up  or  set 
to  the  wind  in  a  cask  in  a  circle  around  it  and  in  the 
middle.  It  is  better  to  full  quite  a  quantity  of  skins  to¬ 
gether,  for  thereby  we  reach  a  better  result  than  if  taken 
singly.  Pour  into  the  cask  two  or  three  pails  of  water 
of  weak  liquor,  then  each  workman  takes  a  pounder  and 
begins  in  time  with  the  next,  to  pound  the  skins  in  the 
tub.  The  strokes  should  never  be  repeated  in  the  same 
place.  In  this  way  the  calf-skins  are  sufficiently  fulled 
in  seven  or  eight  minutes,  upon  one  side.  Turn  them 
about,  and  the  work  begins  again  and  goes  on  till  they 
fall  down,  or  are  fulled  as  soft  as  a  rag. 

In  the  great  workshops  where  mechanical  power  is 
used,  there  must  be  a  fulling  cask.  The  calf-skins  are 
brought  to  it,  bent  into  a  muff  form,  the  proper  quantity 
of  water  or  tanning  liquor  is  poured  in,  and  the  cask  is 
made  to  revolve.  Thus  the  skins  full  and  cleanse  them¬ 
selves.  By  this  much  hand  work  is  saved,  and  the  work 
is  better,  for  they  are  allowed  to  full  the  necessary  length 
of  time  to  become  perfectly  tender ;  while  in  fulling  by 
hand,  the  workmen,  to  whom  the  business  is  not  especially 
pleasant,  perform  it  negligently,  which  is  a  great  fault, 
since  a  bad  calf-skin  fulled  before  the  setting  out  is  almost 
like  a  dry  skin  which  one  should  put  into  the  pit  before 
it  is  prepared  for  the  tanning  process.  Before  the  table 
workman  can  become  master  of  his  skin,  he  must  soften 
it  thoroughly  again,  and  it  should  be  half  cleansed,  that 
the  nerve  may  be  broken.  By  this  the  work  will  be 
forwarded  ;  but  this  process  is  often  slighted,  especially 
in  piece  work,  and  hence  we  would  advise  that  it  be 
performed  by  mechanical  means  whenever  possible. 
When  this  work  is  done,  rinse  the  skins  in  clear  water 
or  in  weak  ooze.  Pure  water  is  preferred. 

The  tools  used  in  the  table  work  are  the  scouring 


448 


CURRYING. 


stone,  the  smoothing-iron  or  sleeker,  and  the  scouring- 
brush.  These  tools  being  well  known,  we  do  not  think 
it  necessary  to  describe  their  form  and  appearance. 
When  the  tools  are  put  into  shape,  take  a  calf-skin  from 
the  cask  where  it  has  been  soaking,  and  place  it 
upon  the  marble,  the  flesh  side  up,  the  tail  part  turned 
to  the  right,  and  the  whole  hinder  portion  of  the  skin 
upon  the  marble,  and  the  neck  four  inches  from  the 
edge. 

Take  the  sleeker  and  go  to  work  on  the  back  strips, 
make  the  first  stroke  in  the  direction  of  the  tail,  beginning 
at  the  shoulders,  and  the  second  stroke  proceeds  from 
the  same  centre,  and  is  directed  straight  along  the  neck 
bet  ween  the  ears.  If  by  both  these  strokes  the  calf-skins 
are  not  smoothed  down  flat  along  the  back,  repeat  them, 
and  begin  them  upon  the  throat  almost  transversely. 
Leave  the  fore  shanks  and  turn  to  the  tail  part  of  the 
calf-skin.  The  strokes  from  the  shoulders  begin  along 
the  back  and  go  on  one  after  another,  taking  in  an  inch 
to  an  inch  and  a  half  in  width,  and  from  twenty  to  twenty- 
four  inches  in  length,  at  every  stroke,  till  you  come  to 
the  navel.  The  purpose  of  this  operation  is  to  free  the 
neck  and  other  parts  from  superfluous  thickness.  First 
of  all,  endeavor  to  even  the  skin  well  and  to  make  the 
thickness  as  uniform  as  possible,  and  to  gain  this  end 
begin  with  the  fulling  of  your  leather  by  the  first  work¬ 
ing,  which  is  the  stretching  of  the  flesh  side. 

When  the  neck  part  is  well  evened  and  the  rear  part 
well  beaten,  stretch  the  skin  as  much  as  you  can,  since 
the  more  you  extend  it  the  thinner  will  the  skin  become 
on  each  side.  The  fore  shanks  are  stretched  and  evened 
by  themselves.  Then  repeat  the  strokes  upon  the  tail 
part,  pressing  hard  upon  the  roots  of  the  tail  and  upon 
the  rear  of  the  skin,  and  when  you  come  to  the  hind 
shanks  trim  these  by  oblique  cuts  right  and  left.  After 
this  gather  up  all  the  cuttings,  take  the  brush,  dip  it 
in  water,  and  wash  off  clean  the  flesh  side  of  the  skin. 
Now  turn  it  about  in  order  to  use  the  iron  upon  the 
other  side,  proceeding  as  before.  Then  fold  the  skin 
square,  and  rinse  it  out  in  clean  water. 


WAXED  CALF-SKINS. 


449 


Take  the  calf-skin  again  and  spread  it  out  upon  the 
marble  just  as  you  did  in  working  the  flesh  side  ;  take 
the  scouring-stone  and  stretch  the  skin,  going  down  from 
the  shoulders  along  the  back  to  the  tail.  Then  turn 
around  and  stretch  it  in  the  direction  of  the  neck,  always 
along  the  back — stretching  it  with  all  your  force.  If 
the  calf-skin  possesses  too  much  nerve,  do  not  hesitate 
to  cover  the  marble  with  a  thin  coating  of  tallow,  so 
that  there  may  be  no  displacement  of  the  skin  at  this 
point.  After  this  is  done,  begin  upon  the  neck,  pressing 
the  stone  upon  it  hard  without  holding  it  too  fast  in  the 
hands.  The  weight  of  the  fore  part  of  the  body  is  enough, 
for  if  you  hold  the  stone  too  firmly,  your  hands  become 
tired  too  soon,  and  as  you  go  to  and  fro  with  the  strokes 
let  the  stone  slide  along  easily  over  the  skin  to  clear  off 
the  grain.  When  you  repeat  the  stroke,  lean  upon  the 
tool,  but  do  not  press  hard  upon  it,  for  strength  would 
be  wasted  to  no  purpose. 

When  the  neck  is  well  stretched,  turn  back  again  in 
the  direction  of  the  rear  of  the  skin,  and  beginning  the 
strokes  at  the  shoulders,  work  down,  taking  about  If 
inch  at  every  stroke  towards  the  navel.  You  come  to 
the  breast  part,  which  you  work  by  straight  strokes  from 
you,  taking  off  the  superfluous  leather  which  appears 
here.  The  fore  shanks  you  stretch  by  cuts  right  and 
left.  Then  take  the  tail  part,  which  you  press  as  hard 
as  you  can,  for  this  part,  always  full  of  nerve,  must  be 
worked  down  at  any  cost.  Then  stretch  the  belly  and 
carefully  work  down  the  hind  shanks.  When  this  is 
done,  take  the  brush  and  carefully  wash  the  grain  side 
with  it,  and  take  the  scouring-stone  again,  letting  it  play 
at  pleasure  over  the  skin.  The  drier  the  operation  be¬ 
comes,  the  more  the  grain  is  compressed.  AH  the  veins 
must  vanish,  and  the  lines  show  themselves  upon  the 
epidermis.  It  is  only  when  you  perceive  this  that  you 
can  regard  your  skin  as  sufficiently  dressed.  Then  take 
your  brush,  wash  the  grain  again,  and  use  the  smoothing- 
iron,  the  blade  of  which  must  be  in  good  order,  in  order 
to  avoid  a  change  in  the  grain.  Use  your  sleeker  in  the 
way  you  did  your  scouring-stone,  only  seize  it  firmer  in 
29 


450 


CURRYING. 


the  hands,  so  that  it  will  not  hop,  and  do  not  touch  it  to 
the  grain  in  the  back  stroke.  We  have  seen  workmen 
who  neglected  to  press  the  skin  with  the  stone,  and 
sought  to  make  the  veins  disappear  by  stretching  the 
skin  by  strength  of  arm  alone,  and  they  did ;  but  when 
their  skin  came  upon  the  marble,  the  veins  appeared 
again,  and  showed  their  work  to  be  incomplete.  The 
scouring-stone  alone  can  take  out  the  veins,  the  stretch¬ 
ing  comes  after  it,  but  cannot  take  its  place. 

When  the  calf-skin  is  well  pressed  and  stretched,  turn 
it  around  and  begin  the  work  on  the  other  side  in  the 
same  way.  Take  good  care  always  to  have  the  back 
strips  well  stretched,  for  the  least  displacement  will 
cause  the  skin  to  be  stretched  crosswise  and  you  should 
be  obliged  to  full  it  over  again. 

After  exposure  to  the  wind,  come  the  stiffening  and 
drying.  In  summer,  after  calf-skins  have  been  tho¬ 
roughly  exposed  to  the  wind,  they  may  be  oiled  without 
being  dried,  but  in  winter  it  is  advisable  to  have  them 
dried,  especially  the  skins  of  males.  In  large  establish¬ 
ments,  there  should  be  a  hydraulic  press  for  that  pur¬ 
pose,  and  the  operation  can  be  done  successfully  by  that 
means,  but  in  ordinary  establishments,  where  machinery 
is  lacking,  the  skins  should  be  exposed  to  the  air  until 
the  moisture  has  completely  evaporated.  This  greatly 
facilitates  the  workmen’s  tasks,  the  skins  tend  better,  and 
the  action  of  the  stretching-iron  is  much  stronger,  and 
the  veins  do  not  rise ;  besides,  the  skin  will  be  more 
compact.  Male  calf-skins  especially  require  much  care, 
chiefly  in  the  necks,  the  flanks,  and  the  edge  of  the 
rump  ;  to  these  portions  an  intelligent  workman  should 
devote  all  his  skill. 

In  stuffing  the  skins,  use  in  summer  a  substance  com¬ 
posed  of  white  whale  oil,  tallow,  melted  by  the  fire,  and, 
in  order  to  combine  these  to  the  fatty  bodies,  add  a  third, 
by  mixing  with  them  a  little  degras  of  the  best  quality, 
in  the  proportion  of  one-fifth  of  degras  to  four-fifths  of 
other  matter. 

In  winter,  in  the  place  of  whale  oil,  use  cod-liver  oil, 
and  try  as  far  as  possible  to  procure  the  cod-liver  oil 


WAXED  CALF-SKINS. 


451 


entirely  pure,  free  from  any  admixture  of  vegetable  oil. 
In  general,  all  animal  grease  may  be  used  to  oil  skins. 
Such  is  not  the  case,  however,  with  vegetable  oils.  Not 
only  do  they  not  impart  any  body  to  the  material,  but 
they  also  give  it  no  softness,  and  they  are  always  apt  to 
escape  from  the  tissue  of  the  skin,  either  on  the  flesh 
side  by  rising  to  the  surface,  or  on  the  grain  side  by 
raising  to  the  epidermis,  forcing  often  little  blisters 
which  burn  the  grain  or  brown  it. 

When  the  skin  has  been  well  dressed  and  stretched 
upon  the  marble  table,  after  every  vein  has  disappeared, 
coat  the  grain  side  slightly,  then  fold  the  skin  and  leave 
it  two  or  three  days  in  this  position  before  oiling  the 
flesh  side.  The  grain  returns  to  its  original  nature 
under  the  wholesome  influence  of  this  application,  which 
penetrates  and  spreads  slowly  through  the  tissues  of  the 
skin,  and  in  three  days  the  entire  coating  of  oil  will 
have  penetrated  all  the  pores  of  the  skin,  the  tallow 
alone  remaining  in  a  paste  on  the  surface,  and  serving 
to  keep  it  fresh,  when  the  skin  is  ready  to  be  exposed  to 
the  air  or  heat  to  dry  it. 

If  you  should  have  smeared  the  flesh  side  with  oil 
immediately  after. the  operation  of  stuffing  the  grain,  the 
workman  who  applied  the  oil,  in  pressing  the  skin  to 
make  it  stick,  would  drive  out  all  the  oil  by  the  pressure 
of  the  stretching-iron,  and  there  would  not  remain 
matter  enough  on  the  grain  side  to  soften  it,  or  to  pre¬ 
serve  it  from  the  too  strong  action  of  the  air  or  the  heat 
of  the  drying  stove,  and  thus  the  object  would  not  be 
attained,  for  we  aim,  above  all  things,  at  obtaining  a  soft, 
pliant,  and  mellow  grain.  In  order  that  this  end  may 
be  entirely  secured,  the  grain  must  have  been  thoroughly 
saturated  with  tannin  during  the  tanning,  and  this  desi¬ 
rable  result  could  not  possibly  be  attained  in  calf-skins, 
when  the  tanning  of  the  grain  has  been  neglected. 
After  the  calf-skins  have  remained  two  or  three  days 
oiled  on  the  grain  side,  you  make  preparations  to  oil 
them  on  the  flesh  side,  and  to  effect  this  operation,  which 
is  one  of  the  most  essential  in  the  preparation  of  calf¬ 
skins,  operate  in  the  following  manner. 


452 


CURRYING. 


In  its  composition,  use  as  far  as  possible  only  degras 
of  the  best  quality.  Sheep  or  buffalo  is  to  be  preferred ; 
it  is  more  penetrating  and  it  leaves  less  deposit  upon  the 
skin.  Both  in  summer  and  also  in  winter,  add  to  it  a 
certain  quantity  of  good  tallow,  and  in  mixing  it  do  not 
melt  all  the  degras.  Out  of  440  lbs.  of  degras  you  melt 
about  110  lbs.  You  have  it  melted  in  a  pot  until  it 
almost  boils,  then  pour  it  gently  upon  the  rest.  Next 
you  melt  a  potful  of  tallow,  which  you  pour  out  at  the 
same  degree  of  heat,  and  you  mix  it  together  briskly  by 
means  of  a  stick. 

When  the  mixture  is  nearly  complete,  take  a  stirring- 
pole  and  keep  on  stirring  the  contents  until  it  is  nearly 
cold,  so  that  the  substance  may  be  so  intimately  mixed 
that  the  part  of  the  separate  ingredients  will  not  appear. 
In  summer,  when  it  is  warm,  double  the  quantity  of  tal¬ 
low,  but  in  winter  graduate  this  according  to  the  tem¬ 
perature.  Sometimes  by  drying  with  a  stove  it  happens 
that  you  use  as  much  tallow  as  in  summer,  so  that  the 
stuffing  be  made  compact  and  not  run  after  it  has  been 
applied. 

This  being  done,  take  the  skin  by  the  two  hinder 
shanks  and  lay  it  on  the  marble  table  as  far  as  the 
shoulders.  Feel  the  rumps  and  the  shanks  to  assure 
yourself  of  their  strength.  Press  it  slightly  upon  the 
marble,  without  using  too  great  an  effort,  so  as  not  to 
displace  the  leather  and  in  order  not  to  remove  the 
matter  applied  to  the  grain  side.  Take  a  smearing  cork 
covered  with  smooth  lamb-skin,  or  rather  a  soft  brush, 
and  dip  it  into  the  degras,  which  stands  on  a  corner  of 
the  table  within  reach.  Take  up  a  certain  quantity  and 
apply  it  to  the  left  buttock  of  the  skin,  then  the  same 
on  the  right  buttock,  and  spread  it  uniformly  all  over. 
Cross  the  sweeps  so  that  the  coating  may  be  every¬ 
where  equal,  taking  care  to  go  softly  over  the  grain, 
then  pass  the  brush  from  one  flank  to  the  other,  and 
from  the  edges  of  the  rump  to  the  shoulder.  After 
doing  this,  apply  a  fresh  coating  to  the  nerves  of  the 
hinder  shank,  to  the  rump,  the  centre,  and  borders  of 
the  belly.  The  skins  being  thoroughly  tanned,  and 


WAXED  CALF-SKINS. 


453 


having  neither  lime  nor  moisture,  will  stand  an  enor¬ 
mous  quantity,  and  you  lay  on  a  coating  almost  equal 
in  thickness  to  the  leather  itself.  The  males,  after  their 
rumps  have  been  well  smeared,  should  have  a  uniform 
coating,  their  buttocks  being  as  thick  as  the  borders ; 
but  with  the  females  it  is  different,  the  borders  of  their 
rumps  and  their  flanks  are  thinner,  and  treat  them  ac¬ 
cordingly.  The  centre  of  these  skins  being  thicker 
and  more  compact  than  in  the  male  skins,  make  repeated 
applications  to  those  parts  until  at  least  one-third  more 
is  added. 

All  the  parts  being  now  placed  on  the  marble,  take  the 
skin  on  the  right  side  of  the  fore  and  hind  shanks,  and 
turn  it  round  briskly.  Then  seize  the  two  breast  points 
and  spread  the  skin  out  smooth.  Take  the  stretching- 
iron  and  press  down  the  neck  gently  so  as  not  to  change 
its  shape,  for  were  you  to  press  it  violently,  the  action 
of  the  stretching-iron  would  displace  the  skin,  and  you 
would  have  much  trouble  in  readjusting  it  and  making 
it  as  straight  as  it  was.  And  even  then  you  would  not 
succeed  so  far  as  to  avoid  leaving  wrinkles  about  the 
neck,  which  is  a  common  defect  among  workmen  in 
applying  oil  to  calf-skins.  Many  do  not  know  how  to 
adjust  a  skin  correctly,  and  nothing  is  more  ugly  than  a 
finished  calf-skin  that  has  wrinkles  on  the  neck,  com¬ 
mencing  at  the  shoulder,  when  spread  out  on  a  table. 

To  resume,  the  calf-skin  lies  down  flat  without  requir¬ 
ing  effort  to  put  it  so,  as  it  has  been  already  stretched 
and  made  even.  Apply  the  degras  to  the  thick  part  of 
the  neck,  then  spread  it  out  and  equalize  it.  Next,  lay 
another  coating  on  the  neck  according  to  its  thickness, 
and  use  more  in  proportion  on  the  nerve  of  the  fore 
shank,  the  brisket  and  the  shoulder ;  but  give  great  care 
to  the  sides  of  the  neck,  for  a  calf-skin  impregnated  with 
oil  about  the  neck  is  very  ugly. 

Nothing  more  unmistakably  indicates  an  inexperi¬ 
enced  oiler  than  a  skin  that  spreads  unevenly  and  shows 
oil  through  the  neck  and  shanks.  After  this  is  finished, 
take  a  little  stick,  which  pass  through  the  holes  that  you 
have  taken  care  to  make  in  the  hinder  shanks,  and  leave 


454 


CURRYING. 


the  skin  to  dry.  You  use  about  6  lbs.  of  degras  to  smear 
50  lbs.  of  calf-skins,  when  taken  out  of  the  pit  on  the 
flesh  side;  and  about  \h  lb.  to  smear  the  same  quantity 
on  the  grain  side. 

The  drying  of  oiled  calf-skins  requires  the  greatest 
care.  In  winter,  when  the  temperature  is  low  and  the 
air  moist,  calf-skins  cannot  be  dried  in  the  open  air,  for 
the  degras  would  remain  on  the  skin,  the  flesh  side 
would  mould,  making  spots,  and  the  color  would  be 
hideous.  Recourse  must  be  had,  therefore,  to  the  drying 
stove,  but  in  this  case  the  heat  should  be  temperate. 
Too  much  fire  is  to  be  avoided,  for  with  calf-skins  freshly 
oiled,  the  greasy  matter  would  decompose  and  run,  and 
as  calf-skins  are  suspended  by  the  rumps,  and  as  this 
portion  receives  twice  as  much  degras  as  the  neck  which 
hangs  down  below,  the  result  would  be  that  in  running 
from  the  rump  downwards,  the  grease  would  penetrate 
the  neck  to  the  detriment  of  the  body  of  the  skin,  which 
would  not  be  supplied  with  enough  grease.  From  86  to 
100°  of  heat  will  be  sufficient.  With  such  a  temperature 
Paris-slaughtered  calf-skins,  oiled  and  fresh  from  the 
pits,  can  be  dried  in  eight  days.  A  drying  room  should 
have  one  or  more  apertures  in  order  to  carry  off  the 
moisture  that  escapes  from  the  skins,  and  thus  the  drying 
is  better  and  more  promptly  effected. 

When  the  calf-skins  are  entirely  dry  stretch  them  out, 
and  have  them  piled  for  twenty-four  hours ;  then  bring 
them  again  into  the  air,  where  you  leave  them  three, 
four,  or  five  days  before  piling  them  up  again.  The 
freshness  of  the  atmosphere  spreads  itself  upon  the  skins, 
and  restores  to  them  that  suppleness  which  cannot  be 
gained  when  dried  in  a  heated  room.  Their  weight  in¬ 
creases  ;  they  are  easier  to  bleach,  and  the  flesh  becomes 
easier  to  cut.  At  the  end  of  three,  four  or  five  days, 
pile  them  up  again,  folded  together,  having  the  flesh  side 
inwards.  Stretch  out  the  edges  and  hams  carefully,  so 
that  no  folds  may  be  made  by  pressure;  then  load  them 
with  weights  as  heavily  as  you  can,  and  leave  them  thus 
for  eight  days  at  least. 

In  regard  to  drying -in  spring  time  it  regulates  itself, 


WAXED  CALF-SKINS. 


455 


and  no  other  precautions  are  necessary  except  to  change 
the  places  of  the  skins  every  now  and  then,  and  to  pile 
them  up  as  they  become  dry. 

In  summer,  when  the  heat  is  excessive,  precautions 
must  be  taken.  We  have  seen  some  calf-skins  dried  in 
twelve  hours,  but  the  flesh  side  was  streaked  like  marble, 
and  the  flanks  burned  by  the  heat.  In  bleaching  those 
skins  the  dust  flew  up  before  the  scraping-iron.  Often 
the  greatest  trouble  is  experienced  in  restoring  them  to 
their  proper  degree  of  drying  heat.  The  best  method 
when  that  happens  is  to  pile  the  skins  up  in  a  cellar  or 
other  damp  place,  and  leave  them  there  eight  days  with¬ 
out  changing  the  pile.  At  the  end  of  that  time  bring 
them  up  out  of  the  cellar,  and  pile  them  in  the  ware¬ 
house,  where  you  leave  them  as  long  as  you  can  in  oil. 
Thus,  the  flesh  side  becomes  equalized,  and  the  coating 
of  tallow,  remaining  on  the  flesh,  combines  intimately 
with  it.  When  they  are  handed  to  the  bleacher  they 
cut  well,  and  the  difficulty  is  thus  removed,  although 
not  without  a  loss  in  weight. 

The  season  most  propitious  for  perfect  success  in  oiling 
is  during  the  months  of  September  and  October,  the 
heat  being  then  temperate  during  the  day;  the  nights 
are  cool;  the  process  of  drying  goes  forward  slowly  and 
surely  ;  the  material  retains  its  suppleness  and  weight  ; 
it  is  easily  finished,  and  the  quality  is  perfect. 

After  the  skins  have  laid  the  proper  length  of  time, 
clear  them  of  fat  upon  the  flesh  and  grain  sides.  For 
this  purpose  use  a  small  stretching-iron,  not  pliant,  which 
you  whet  upon  the  sandstone  till  it  is  tolerably  sharp, 
but  do  not  bend  around  its  edges  for  reasons  which  we 
will  indicate.  Lay  the  calf-skin  lengthwise  upon  the 
marble  table,  and  press  heavily  upon  the  iron,  which  is 
half  bent  towards  the  body  ;  the  strokes  are  given  in  the 
same  direction  you  took  before  you  oiled  the  skins;  smooth 
out  carefully  the  folds  which  sometimes  appear  along  the 
edges.  Take  good  care  not  to  open  the  flanks,  and  those 
parts  of  the  skins  which  have  been  worked  togeher,  so 
as  not  to  disfigure  the  skin.  This  would  be  an  evil  that 
could  hardly  be  obviated,  as  all  the  disfigured  parts  lie 


456 


CURRYING. 


in  folds  and  wrinkles,  and  can  never  be  made  even  again. 
How  often  have  we  seen  calf-skins  cleared  of  fat  by  in¬ 
competent  workmen  in  such  a  way  that  the  finisher 
could  never  restore  them  to  a  good  condition.  He  lost 
time  and  lessened  the  weight  of  the  goods  in  the  effort, 
but  gained  nothing.  Therefore,  watch  this  process  to 
avoid  the  above-mentioned  bad  result,  and  do  not  bend 
up  the  edge  of  the  instrument  used  in  the  operation,  so 
that  you  can  give  the  stroke  according  to  your  liking, 
and  avoid  making  useless  notches  in  your  skins.  If  you 
wish  to  shave  the  calf-skins,  take  the  folds  out  of  them 
lightly  and  gently  with  a  blunt  sleeker. 

Bleaching  or  Whitening. — The  bleaching  of  waxed 
calf-skins  is  one  of  the  most  essential  processes  in  its 
manufacture.  It  is  the  beginning  of  the  end,  and  the 
defects  of  the  bleacher  will  be  noticeable  by  all,  even  by 
inferior  judges.  A  streaked  calf-skin  attracts  attention, 
and  an  ill-finished  flesh  side  cannot  be  kept  out  of  sight. 
Any  slight  cut  should  be  made  to  disappear;  if  not,  it 
will  remain  as  a  defect,  exposed  to  the  view  of  the  buyer. 
Therefore,  to  make  a  good  bleacher,  a  man  needs  to  be 
skilful  and  intelligent  at  the  same  time,  otherwise,  he 
will  be  unable  to  turn  out  a  perfect  article. 

The  manufacture  of  waxed  calfskins  in  France  became 
so  largely  developed  in  the  years  subsequent  to  1830, 
that  workmen  capable  of  performing  the  bleaching  pro¬ 
cess  with  the  knife  could  not  be  taught  fast  enough. 
Another  motive,  and  one  equally  powerful,  the  sale  of 
calf-skins  by  weight,  forced  the  manufacturers  to  look 
to  it. 

The  manufacturers  of  the  Loire-Inferieure,  the  Nantes 
tanners  were  the  first  to  meet  with  these  difficulties. 
Some  workmen  who  did  not  like  over  much  to  whet 
their  tools,  and  who  were  required  to  clean  their  skins 
when  green,  thought  fit  to  set  the  edges  of  their  stretch¬ 
ing-iron  bluntly,  and,  not  satisfied  with  removing  the 
dirt  from  the  skins,  they  also  took  off  the  small  morsel 
of  flesh  remaining.  The  better  instructed  perceived 
this,  and  sought  to  draw  advantage  from  this  nascent 
invention.  They  bought  good  blades  made  of  steel, 


WAXED  CALF-SKINS. 


457 


which  were  carefully  ground,  and  the  edge  curved  con¬ 
versely.  With  a  fine  butcher’s  steel  the  edge  was  set, 
and  the  workmen  began  to  scrape  properly.  By  degrees 
the  more  expert  among  the  workmen  got  their  hands 
used  to  this,  and  the  process  of  bleaching  with  the 
stretching-iron  became  improved.  Necessity,  the  great 
mother  of  invention,  did  not  fail  the  seekers  in  this 
respect.  Bleachers  with  the  knife  gained  auxiliaries, 
and  orders  were  no  longer  delayed  in  the  filling  through 
the  lack  of  competent  workmen.  When  a  stretching- 
iron  is  wielded  by  a  skilful  and  intelligent  operator,  it 
may  be  made  to  take  the  place  of  the  knife;  better  than 
this,  calf-skins  are  less  put  out  of  shape  and  better  pre¬ 
pared  by  being  bleached  with  a  stretching-iron.  But 
how  few  workmen  combine  the  requisite  qualifications, 
and  how  many  among  those  who  possess  them  will  not 
give  themselves  the  trouble  to  do  it  well! 

In  order  to  bleach  a  calf-skin  well  with  the  stretching- 
iron,  it  must  first  be  worked  lengthwise  and  then  gone 
over  transversely  with  care,  working  without  interrup¬ 
tion,  removing  the  veins  and  knots  of  flesh,  and  especially 
the  cuts,  at  least  those  which  can  be  made  to  disappear. 
By  taking  all  these  precautions,  a  skin  is  often  turned 
out  that  ranks  in  the  first  quality,  otherwise  some  have 
ranked  only  as  second  fate. 

The  cost  of  the  operation  of  bleaching  with  the  knife, 
for  medium-sized  Paris-slaughtered  calf-skins,  amounts 
to  forty  cents  per  dozen,  and  of  bleaching  the  same  skins 
with  the  stretching-iron  to  thirty-five  cents  per  dozen. 
It  is  to  be  understood  that  for  this  price  the  workman 
should  remove  all  such  defects  as  can  be  made  to  dis¬ 
appear — in  fact,  he  should  put  his  calf-skins  in  full  dress. 

The  skins  that  are  finished  up  with  the  shaving-knife, 
although  they  are  cleared  of  fat  before  the  process,  cannot 
be  grained  without  being  gone  over  a  second  time.  The 
reason  of  this  is  that  the  corners  of  the  beam  in  shaving 
often  make  impressions  upon  the  skin  which  subsequent 
operations  cannot  remove,  and  these  marks  injure  the 
looks  of  the  skin.  After  this,  we  advise  the  following 
means :  Take  a  light  brass  grainer,  round  off  its  corners 


458 


CURRYING. 


well,  and  put  it  first  upon  the  sandstone,  then  upon  the 
English  stone  till  it  is  polished  almost  as  bright  as  a 
mirror,  then  take  the  skins  crosswise  as  in  the  working 
in.  In  order  to  avoid  making  wrinkles,  remove  all  irre¬ 
gularities  from  the  board,  stretch  the  necks  and  flanks 
straight,  take  off  and  even  the  folds  which  have  appeared 
in  drying.  Remove,  by  a  single  strong  pressure,  the  veins 
which  withstood  the  stretching  process,  or  which  have 
appeared  since  that.  This  operation  makes  the  grain 
remarkably  pliable  and  uniform.  Then  take  a  pushing- 
iron,  not  too  pliable,  make  its  edges  very  smooth,  so  that 
it  will  not  be  apt  to  gnaw  in  or  make  furrows.  Begin 
now  at  the  neck  to  clear  the  skin  and  to  compress  it. 
Take  special  care  to  avoid  scratches,  which  give  to  the 
grain  a  marbled  look  and  injure  the  whole  of  the  curry¬ 
ing  work.  This  important  operation  is  too  often  put 
into  unskilful  hands,  and  is  executed  very  badly.  Many 
manufacturers  attach  little  importance  to  it,  but  we 
think  it  is  best  to  devote  to  it  great  attention.  First, 
it  imparts  to  the  grain  a  greater  softness,  while  it  also 
strengthens  the  fibres  of  the  hide.  You  prepare  the 
way  for  giving  a  grain  to  the  skin,  and  with  a  skin  pre¬ 
pared  in  this  way  beforehand  one  is  sure  of  a  grain  of 
fine  appearance.  It  is  very  difficult  to  grain  a  fine  calf¬ 
skin  alike  in  all  parts  if  this  operation  has  not  been  first 
performed. 

In  the  same  way  treat  calf-skins  that  have  been  whit¬ 
ened  with  the  knife  for  that  purpose,  and  such  as  have 
been  entirely  cleared  of  fat  before  whitening.  The  tallow 
which  remains  upon  the  grain  hardens  and  equalizes 
itself  under  this  operation  of  dry  finishing.  The  grain 
will  again  become  pliable  and  free,  and  often  calf-skins 
that  have  been  too  quickly  dried  or  rather  bathed  in  the 
drying-room,  or  in  the  air  in  summer  heat,  are  restored 
and  made  very  soft.  It  is  this  way  of  working  by  which 
one  gets  that  pearly  yet  tender  grain,  which  to  the  com¬ 
mon  eye  is  a  sign  of  fine  work. 

Graining. — There  are  several  ways  of  graining  calf¬ 
skins.  Almost  every  manufacturer  has  a  peculiar  method. 
Some  make  a  cross  grain  by  taking  their  skins  from  the 


WAXED  CALF-SKINS. 


459 


four  quarters ;  this  is  the  English  method.  Others  make 
a  barley  grain,  and  in  our  opinion  this  grain  is  the  hand¬ 
somest,  for  it  breaks  the  skin  less  and  spares  the  flanks 
more.  Others  start  it  from  the  four  quarters  and  end  it 
by  running  straight  from  head  to  tail,  which  produces 
a  very  fine  grain,  but  it  can  only  be  done  successfully 
with  female  skins  that  have  been  very  compactly  tanned, 
and  would  not  do  for  male  calf-skins. 

In  order  to  grain  a  skin  well  one  requires  to  be  prac¬ 
tically  acquainted  with  skins  so  as  to  be  able  to  judge  at 
the  first  glance  of  the  quality  of  the  skin  to  be  grained, 
for  if  a  calf-skin  is  firm  and  compact,  it  can  be  dressed 
with  cork  without  danger,  and  without  fear  of  bringing 
too  coarse  a  grain  to  the  surface.  But  this  is  not  the 
case  with  calf-skins  that  are  a  little  flabby  ;  their  grain 
is  tender,  and  they  should  be  treated  carefully  or  the 
grain  surface  will  rise  so  that  it  will  seem  to  be  detached 
from  the  fibres. 

This  is  the  way  to  proceed  in  this  operation;  Take  a 
grain er  not  over  62  inches  in  breadth,  and  covered  uni¬ 
formly  with  cork.  The  grain  should  not  be  too  convex, 
and  should  form  an  elliptical  arch,  and  its  length  may 
vary  from  10  to  11  inches.  In  the  centre  have  a  band 
of  leather  at  the  back,  broad  and  soft  so  as  not  to  hurt 
or  fatigue  the  hand.  This  instrument  should  be  very 
light  and  easy  of  use,  as  it  is  almost  always  worked  with 
one  hand,  and  this  hand  would  soon  become  fatigued  if 
the  instrument  were  not  of  this  condition  as  to  its  light¬ 
ness  and  adaptability  to  the  hand.  Take  the  skin  by 
the  left  shank  and  roll  this  shank  closely  until  you  come 
to  the  navel,  so  as  to  fix  the  direction  of  the  grain  that 
you  wish  to  produce,  starting  from  the  left  brisket  to 
the  right  hinder  shank.  If  the  skin  is  firm,  pass  the 
cork,  holding  it  by  the  right  hand,  under  the  left,  and 
bear  down  heavily  with  both  hands,  taking  care  to  follow 
the  corners  of  the  cork,  which  is  essential  to  curve  the 
grain,  for  if  you  draw  it  straight  the  grain  will  remain 
fiat.  You  follow  up  without  interval,  taking  care  to 
push  from  left  to  right  only  a  distance  equal  to  one- 
quarter  of  the  breadth  of  the  cork  in  order  to  produce  a  uni- 


460 


CURRYING. 


form  grain.  When  you  reach  the  right  flank,  do  not 
crush  it,  but  pass  lightly  over  it,  pressing  only  lightly 
on  your  cork  until  you  reach  the  hinder  shank,  when 
you  press  heavily. 

The  grain  being  well  brought  out  through  the  whole 
length,  unroll  the  skin  and  continue,  passing  carefully 
over  the  left  flank,  and  pressing  heavily  upon  the  rump, 
for  the  grain  of  this  part  does  not  develop  itself  as  easily 
as  elsewhere,  and  often  a  double  amount  of  work  is  re¬ 
quired  there.  Still  bringing  out  your  skin,  you  arrive 
in  this  manner  at  the  end  of  the  shank,  then  you  turn 
the  skin  around  to  work  on  the  neck.  This  part  you 
also  roll  and  begin  your  grain  again  in  the  middle  where 
the  other  commenced;  there  you  proceed  in  the  same 
manner,  going  carefully  over  the  weak  parts  and  press-, 
ing  heavily  upon  the  neck  in  order  to  break  it  down. 
When  you  reach  the  extremity,  take  the  skin  straight 
before  you  and  roll  up  all  the  throat  and  neck  with  the 
left  hand,  thus  reaching  to  the  middle  of  the  skin,  there 
hold  it  rolled  up  with  the  left  hand,  while  with  the  right 
you  curve  the  grain  lengthwise  in  a  uniform  manner. 

Mode  of  making  the  Blacking  and  its  Applications. — 
The  blacking  is  made  in  the  following  manner:  Take 
good  light  lampblack  and  let  it  soak  in  linseed  oil  for 
several  hours.  If  you  wish  to  make  a  quantity  of  black¬ 
ing,  put  in  one-tenth  lampblack,  which  gives  a  beau¬ 
tiful  color  and  does  not  dirty  the  brush.  After  it  is 
well  saturated  in  a  small  quantity  of  oil,  crush  it  to 
mash  the  lumps  either  with  the  hands  or  upon  a  marble 
slab  with  a  roller  prepared  for  the  purpose.  When  it 
becomes  of  the  consistency  of  paste,  and  after  all  the 
lumps  have  disappeared,  pour  oil  upon  it  and  mix  slowly. 
In  winter  mix  in  linseed  oil,  but  in  summer  put  one-half 
cod-liver  oil,  as  the  linseed  oil  penetrates  and  spots  the 
skin.  To  this  mixture  of  lampblack  and  oil  add  an  ox¬ 
gall  and  five  quarts  of  beer  black,  or  rust  black,  or  bark 
prepared  with  logwood,  verdigris,  gall-nuts,  and  gum 
Arabic.  This  last  black  is  very  handsome,  and  gives  a 
magnificent  blue-black  basis.  After  the  whole  has  been 
well  mixed,  making  a  solid  paste,  next  melt  of  the  tallow 


WAXED  CALF-SKINS.  461 

twice  the  weight  of  the  lampblack  in  winter.  You  only 
melt  it,  and  do  not  let  it  become  too  much  heated,  for  if 
boiled  it  would  coagulate  and  make  little  lumps  when 
poured  out.  It  is  sufficient  to  simply  melt  the  tallow 
before  pouring  it  off,  and  as  soon  as  it  is  poured  it  should 
be  vigorously  mixed.  By  this  method  the  blacking  will 
always  turn  out  well.  In  summer  use  three  times  as 
much  tallow  as  blacking,  and  we  have  known  manufac¬ 
turers  who  added  yellow  wax  with  a  very  good  result, 
especially  in  small. calf-skins,  as  this  often  imparts  a 
certain  appearance  of  solidity  to  the  flanks  which  in¬ 
creases  the  general  effect  to  the  eye. 

Let  the  blacking  become  thoroughly  cold  before 
using  it.  Take  a  dozen  skins,  and  place  the  largest 
undermost,  arranging  them  on  the  table  so  as  to  black 
them  rapidly  and  avoid  any  marks  being  made  by  the 
brush.  Lay  all  the  skins  with  the  flesh  side  uppermost, 
as  a  matter  of  course,  and  the  whole  rump  part  as  far 
as  the  forepaw,  so  that  in  turning  the  skin  around  you 
may  only  have  a  small  part  of  the  neck  still  to  black. 
Having  done  this,  take  your  blacking-brush,  which  is  of 
the  shape  of  a  mushroom  upside  down.  Take  it  in  the 
right  hand  and  dip  it  evenly  in  the  blacking,  taking  care, 
however,  to  use  only  a  small  quantity..  Place  it  on  the 
rump  and  rub  the  flesh  briskly,  sweeping  the  brush 
angularly,  so  as  to  apply  it  thoroughly,  and  use  the  left 
hand  at  the  same  time  as  the  right  to  increase  the  pres¬ 
sure.  The  strokes  are  made  from  the  rump  towards  the 
neck,  and  when  you  reach  that  part  the  brush  is  almost 
dry.  In  order  to  avoid  penetrating  that  part,  which  is 
always  weaker  than  the  rump,  pass  at  once  carefully  to 
the  borders,  where  you  use  very  little  blacking.  Take 
care  not  to  let  the  brush  touch  the  under  sides  of  the 
borders,  so  as  not  to  leave  any  spots  of  blacking  for  the 
reason  that  the  skins  may  be  kept  clean  for  the  subse¬ 
quent  process  and  that  you  may  not  have  to  clean  them 
with  the  stretching  iron. 

After  the  skin  has  become  quite  black,  rub  your  brush 
dry  to  remove  the  dirt,  and  even  leave  the  brush  and 
rub  with  the  hand,  so  as  to  roll  all  the  small  lumps,  and, 


462 


CURRYING. 


after  the  blacking  has  dried  thoroughly,  take  a  horse¬ 
hair  broom  and  sweep  them  off  at  the  skin.  When 
this  operation  is  well  done,  the  finger  may  be  applied 
almost  without  being  blackened  by  the  contact.  This 
is  the  way  to  see  whether  a  skin  is  well  blacked. 
Having  finished  the  rump,  turn  the  skin  round,  and  lay 
upon  the  left  hand  edges  of  the  skin  remaining  upon 
the  table  a  piece  of  leather  or  pasteboard,  so  as  to  pre¬ 
vent  the  blacking,  upon  the  edges  of  other  skins,  from 
staining  the  grain  of  the  skin  which  you  turn,  after 
which  you  black  the  neck  in  the  same  manner  as  the 
rump. 

A  fault  of  many  blackers  is  that  they  spread  the 
blacking  without  brushing  it  in  enough.  This  is  more 
rapid,  but  not  as  good,  for  often  in  sizing  the  skin  for 
the  first  time,  the  brush  raises  the  flesh,  and  the  skins 
turn  out  gray  instead  of  black  ;  and  even  when  the  skins 
are  quite  smooth,  the  flesh  remains  reddish  in  color, 
which  becomes  apparent  when  they  are  sized  for  the  last 
time,  but  then  it  is  too  late  to  remedy  the  evil. 

A  good  blacker  is  a  valuable  workman,  for  when  a 
skin  is  too  pale  after  having  been  oiled,  he  will  darken 
its  color ;  if  it  should  be  too  much  saturated,  he  will 
also  skilfully  avoid  adding  to  this.  This  operation, 
therefore,  requires  an  experienced  man,  one  thoroughly 
acquainted  with  his  task.  For  medium  Paris-slaugh¬ 
tered  calf-skins  this  process  costs  eighteen  or  twenty 
cents  per  dozen,  for  an  active  expert  workman  cannot 
get  through  more  than  from  five  to  six  dozen  per  day. 

Finishing. — Prepare  your  wax  in  the  following  man¬ 
ner:  Take  some  cuttings  of  glovers’ skins  (these  parings 
should  be  kid,  we  prefer  such  to  all  others,  for  goat¬ 
skins  will  give  a  much  finer  glue,  and  consequently  it 
will  be  easier  to  use),  and  let  these  parings  soak  in 
water  during  twelve  hours,  then  rinse  them  well  so  that 
no  foreign  substance  may  remain  with  them. 

If  you  wish  to  make  three  pounds  of  gelatine,  take 
one  pound  of  these  cuttings  and  boil  them  in  five  quarts 
of  water.  Skim  off  the  first  boiling  carefully,  and  then 
let  it  boil  for  about  three  hours  over  a  slow  fire.  At  the 


WAXED  CALF-SKINS. 


463 


end  of  that  time  strain  it  through  a  cloth,  and  let  the 
liquid  cool  down.  By  this  means  you  obtain  a  tender 
gelatine,  which  breaks  easily.  It  should  not  be  too 
strong,  for  it  would  then  break  with  difficulty,  and  as 
you  mix  it  with  tallow  it  would  not  mix  readily,  if  it 
was  too  hard,  and  it  will  be  difficult  to  employ.  More¬ 
over,  if  the  gelatine  were  too  strong,  it  would  prevent 
the  polishing  process,  and  the  calf-skins  will  be  streaked. 

The  great  fault  of  many  finishers  is  in  using  a  first 
glue  of  too  strong  a  consistency. 

Therefore  take,  according  as  you  may  need,  say  two 
lbs.  and  one-fifth  of  the  gelatine,  which  you  break  up 
by  means  of  a  piece  of  wood  kept  for  this  purpose,  and 
you  crush  it  during  ten  minutes;  then  take  If  lb.  of 
tallow  melted  by  boiling.  Crush  this  tallow  thoroughly, 
and,  in  order  to  make  it  more  pasty,  mix  with  it  about 
2>h  ounces  of  linseed  oil  in  summer,  and  7  ounces  in 
winter  ;  for  when  the  temperature  is  low  tallow  hardens, 
and  this  quantity  of  oil  is  necessary  to  render  it  more 
easy  of  handling. 

When  the  tallow  is  well  crushed,  mix  it  by  degrees 
with  the  gelatine  forming  one  substance  of  the  two  ; 
this  mixture  should  be  made  with  much  care. 

Use  in  preference  to  other  sorts,  good  beef  tallow,  and 
have  it  always  melted  by  boiling.  It  is  preferable  to 
mutton  tallow,  which  is  too  dry,  and  always  more  diffi¬ 
cult  to  crush  than  beef  tallow.  Never  use  decomposed 
size,  for  it  always  gives  the  worst  results.  The  material 
being  well  mixed  take  a  soft  brush,  so  that  it  will  not 
streak.  Place  the  skin  on  the  table,  and  brush  it  with 
a  hand-brush  lightly,  to  rid  it  of  any  dust  or  pellets  of 
waxing  that  may  adhere  to  it  still ;  then  with  the  size 
brush  spread  the  skin  over  with  the  first  sizing,  using  a 
small  quantity  for  the  females,  and  a  larger  quantity  for 
the  males.  With  the  latter,  take  especial  care  to  cover 
the  flanks  well,  and  especially  the  necks  of  those  that 
are  old.  Equalize  the  whole  by  a  last  light  brushing, 
and  then  turn  the  skin  over,  and  go  through  a  like  ope¬ 
ration  on  the  other  side. 

Having  done  this,  hang  up  the  skin  to  a  wooden  bar 


464 


CURRYING. 


with  hooks,  by  a  little  hole  made  in  the  centre  of  the 
throat. 

Let  each  skin  hang  in  summer  only  during  the  time 
that  it  takes  to  size  four  skins,  and  in  winter  while  you 
are  doing  six.  Do  not  let  the  size  dry  longer  than  this, 
for  it  would  be  too  difficult  to  polish.  Therefore,  un¬ 
hook  the  skins  as  you  go  on,  and  pile  them  up  on  the 
trestles. 

After  the  first  coating  of  size  has  been  given  to  all  the 
skins,  prepare  to  polish  them  ;  and,  for  this  purpose,  turn 
the  pile  of  skins  upside  down,  so  that  those  first  polished 
may  be  those  that  are  first  sized. 

For  this  operation  a  very  smooth  polishing  surface  is 
necessary,  for  that  no  straps  may  be  made.  Polishing 
may  be  done  upon  smooth  marble,  or  upon  a  table  of 
walnut  wood,  and  many  are  polished  upon  a  foundation 
of  leather.  When  the  skins  are  large,  and  too  much 
charged  with  oil,  it  is  better  to  polish  them  upon  marble. 

If  the  skins  are  medium  sized  and  in  the  same  condi¬ 
tion,  polish  them  upon  a  walnut  table;  but  if  you  have 
small  skins  or  skins  that  are  too  full,  it  is  better  to 
polish  them  upon  a  foundation  of  leather,  and  take  care 
to  spread  a  little  talc  upon  this  basis  from  time  to  time, 
so  that  the  skin  may  slide  over  it  easily,  and  not  stick, 
thus  avoiding  any  crisping  in  the  polishing  process. 

Polish  all  the  skins  transversely  and  often  ;  when  you 
find  skins  which  do  not  polish  easily,  work  them  length¬ 
wise  and  crosswise.  Always  begin  at  the  neck,  and 
make  the  strokes  consecutive,  avoiding  any  crisping  or 
marks  that  will  remain  and  appear  at  the  last  sizing. 

If  the  skins  are  not  oily,  you  need  not  fear  to  darken 
them,  and  polish  them  vigorously ;  but  if,  on  the  con¬ 
trary,  they  are  brown  already,  you  pass  over  them  as 
lightly  as  possible,  so  as  to  avoid  darkening  their  color 
still  more. 

These  two  operations  require  great  care  and  cleanliness. 
Before  turning  the  skin  over  to  give  it  the  first  sizing, 
take  care  to  wipe  the  table  with  a  woollen  rag  to  remove 
the  marks  of  the  brush  which,  after  the  skin  is  turned, 
would  soil  the  flesh  side,  and  oblige  you  to  scrape  it 


WAXED  CALF-SKINS. 


465 


clean  with  the  stretching-iron,  which  would  leave  ugly 
traces  on  the  grain  side  of  the  skins. 

Pursue  the  same  plan  in  polishing;  and  in  this  manner 
the  skins  are  always  scrupulously  clean  on  the  flesh  side; 
and  in  our  opinion  these  are  precautions  that  should  not 
be  neglected,  for  a  skin  spotted  on  the  flesh  side  always 
denotes  a  careless  workman. 

After  these  two  operations  are  finished,  you  prepare 
to  give  your  skins  their  last  sizing.  This  size  is  made 
up  in  the  following  manner;  First  melt  your  gelatine, 
then  add  a  quart  of  water  to  reduce  its  strength,  and  let 
it  cool  otf.  Next  crush  it  with  the  size-beater,  and  mix 
in  a  little  black  soap,  and  3£  ounces  of  tallow  to  each 
pound  of  gelatine.  Then  add  about  a  quart  of  size  in 
paste  with  the  addition  of  a  little  linseed  oil  to  render 
it  more  easy  to  dry,  and  mix  the  whole  mass  together 
with  great  care.  Thanks  to  this  composition,  you  pro¬ 
duce  a  fine  lustreless  size,  which  is  the  most  agreeable 
to  the  eye  and  the  most  advantageous,  for  it  conceals  all 
small  defects. 

But  if  you  wish  to  obtain  a  finer  and  cleaner  size,  you 
set  about  it  in  this  manner:  Dissolve  in  water  some 
white  or  black  soap  (white  soap  is  preferable),  and  let  it 
boil  thoroughly,  so  that  the  soap  may  be  perfectly  dis¬ 
solved,  then  put  in  your  pound  of  gelatine,  which  dissolves 
at  once,  and  while  the  whole  is  boiling  gently,  stirabout 
7  ounces  of  size  paste  into  a  quart  of  water  in  a  separate 
vessel.  When  this  has  mixed  well  pour  it  into  the  first 
vessel  and  let  the  whole  boil  together  thoroughly.  Skim 
it  carefully,  and  at  the  end  of  ten  minutes  take  the  size 
off  the  fire,  strain  it  through  a  cloth  and  leave  it  to  cool, 
taking  care  to  stir  it  from  time  to  time  until  it  acquires 
the  desired  consistency.  After  it  is  quite  cool  crush  it, 
and,  without  adding  anything  further,  you  are  ready  to 
give  the  skins  their  last  sizing.  This  size  is  very  fine 
but  rather  light. 

Lustreless  size  is  properly  appreciated  both  in  France 
and  this  country.  The  English  do  not  like  calf-skins 
sized  according  to  the  French  process,  and  they  bring 
their  calf-skins  white  and  all  ready  to  be  waxed.  In 
30 


466 


CURRYING. 


waxing  and  sizing  them  according  to  their  method,  they 
generally  wax  them  with  very  light  wax,  and  size  them 
with  a  size  much  more  solid  than  the  above,  but  their 
size  has  this  defect,  that  it  turns  gray  with  age.  In 
putting  on  the  last  size  make  use  of  a  very  fine  sponge  ; 
dip  it  in  water,  and  then  squeeze  it  strongly  so  that  the 
least  possible  mixture  may  remain  in  it.  Take  the  skin 
and  spread  it  out  on  the  table  with  the  rump  towards 
you,  then  seize  the  sponge  and  take  a  quantity  of  size  in 
proportion  to  the  dimension  of  the  skin.  Dip  the  sponge 
as  deep  as  possible  into  the  size  and  draw  it  briskly 
towards  the  rump,  then  work  it  right  and  left  to  spread 
the  size,  and  smooth  the  whole,  commencing  at  the  edges 
of  the  rump  and  the  hinder  paws.  Follow  your  sweeps 
quickly,  advancing  towards  the  neck,  pulling  the  skin  by 
the  tail  with  the  left  hand ;  as  the  right  hand  advances, 
the  left  descends,  and  thus  you  reach  the  neck  trans¬ 
versely,  of  course.  By  this  method  you  rarely  spill  any 
of  the  size.  The  first  dip  fills  the  sponge,  and  this 
suffices  for  the  whole  skin.  Then  hook  it  up  to  the  bar 
and  leave  it  to  dry  for  at  least  twelve  hours.  This  ope¬ 
ration  should  take  place  in  a  room  where  neither  steam 
nor  dampness  can  penetrate,  for  either  of  these  influences 
would  tarnish  the  size,  and  in  certain  cases  where  the 
skins  are  put  together  by  dozens,  they  would  stick  the 
one  to  the  other,  and  the  goods  would  at  the  same  time 
lose  in  appearance  and  value. 

These  precautions  are  especially  necessary  when  the 
skins  are  destined  to  be  exported  to  a  long  distance;  for 
a  case  of  calf-skins  that  comes  to  hand  glued  together  is 
greatly  depreciated.  For  this  reason,  in  goods  manufac¬ 
tured  for  exportation,  too  much  care  cannot  be  taken  to 
allow  the  size  to  dry  thoroughly.  Twenty-four  hours  are 
often  necessary,  especially  in  winter  and  in  foggy  weather 
when  the  air  is  overcharged  with  moisture.  At  such 
times  the  rooms  in  which  the  skins  are  placed  to  dry 
should  be  heated  from  60°  to  70°  and  carefully  venti¬ 
lated,  so  that  no  steam  may  remain  to  condense  and 
adhere  to  the  size,  which  would  scarcely  be  noticeable 
upon  taking  the  skins  down,  but  which  after  causes  a 


TV  AXED  CALF-SKINS. 


467 


reaction  at  the  end  of  a  few  days,  especially  when  the 
skins  are  piled  or  packed  up,  and  then  it  is  too  late  to 
remedy  it.  The  calf-skins  arrive,  having  lost  their  fine 
appearance,  for  the  want  of  due  care  in  the  last  ope¬ 
ration. 

It  is  better  to  let  the  calf-skins  rest  in  the  wax  a  while 
for  the  following  reasons  :  Although  the  skin  be  well 
rubbed  and  dry  under  the  brush,  yet  the  fatty  particles 
of  which  the  wax  is  composed  quickly  penetrate  it;  but 
if  it  has  been  dressed  too  thin  in  finishing,  the  impres¬ 
sion  is  momentary  and  gives  the  grain  a  marbled 
appearance.  We  must  let  it  take  its  time  in  quiet,  in 
summer  eight  days,  and  in  winter  from  ten  to  twelve 
days  are  sufficient.  After  this  pile  them  up  in  dozens, 
and  take  care  to  cover  them  up  properly  to  protect  them 
from  the  dust. 

A  workman  who  makes  waxing  his  business,  always 
prefers  calf-skins  whitened  with  the  shaving-knife;  the 
flesh  side  gone  over  more  lightly,  is  brushed  better,  the 
penetration  of  the  dressing  is  more  perfect  and  speedy; 
it  is  easy  to  clean,  which  is  not  so  with  skins  finished 
up  with  the  instrument  for  the  purpose.  With  this  the 
flesh  side  is  left  open  ;  the  wax  penetrates  them  with 
difficulty,  and  it  often  happens  that  the  workman,  in 
order  to  get  along  faster,  makes  his  wax  thinner,  and 
runs  the  risk  of  not  penetrating  them  sufficiently.  Calf¬ 
skins  which  have  been  whitened  with  the  shaving-knife 
gain  more  in  weight  in  waxing  than  those  whitened  with 
the  knife  for  the  purpose ;  but  it  must  not  be  forgotten,  in 
comparing  the  two,  that  the  former  lose  in  shaving  as 
much  as  they  gain  in  waxing,  so  that  after  waxing  the 
difference  between  the  two  has  disappeared. 

We  give  the  preference  to  calf-skins  whitened  with 
the  shaving-knife,  and  the  English,  who  are  celebrated 
for  the  fineness  and  finish  of  the  flesh  side,  never  use 
anything  else.  The  American  curriers,  who  have  derived 
their  principles  from  the  English,  likewise  give  their 
preference  to  calf-skins  whitened  with  the  shaving  knife. 


468 


CURRYING. 


CHAPTER  CXX. 

GRAINED  CALF-SKINS. 

The  first  operation  consists  in  moistening  the  skins 
selected  for  this  manufacture.  This  done,  pare  down 
the  heads  in  order  to  equalize  the  thickness;  place  them 
on  the  table,  and  scrape  them  with  the  stretching-iron. 

Next,  beat  them  with  the  pestle  in  a  tub  of  water, 
smooth  them  on  both  sides  upon  the  marble,  in  order  to 
reduce  the  natural  grain  of  the  leather ;  then  dry  par¬ 
tially.  Apply  the  blacking  on  the  hair  sides;  smooth 
the  skins  again,  and  oil  them  on  both  sides.  Dry  them, 
and  deprive  them  of  the  excess  of  oil  by  means  of  a  lye 
of  potash.  Smooth  them  upon  the  grain  with  the 
stretching-iron. 

In  order  to  furrow  the  surface  with  the  grain,  place 
the  leather  upon  the  table,  with  the  hair  side  up,  and 
pommel  first  crosswise,  then  from  tail  to  head,  being 
careful  that  the  lines  which  correspond  in  direction  shall 
be  perfectly  parallel.  Use  for  this  purpose  a  pommel 
with  45  to  50  teeth  to  the  inch. 

Apply  another  coating  of  black,  and  when  absorbed 
brush  over  the  surface  oil  and  scouring  train  oil,  in  suffi¬ 
cient  quantity  for  the  requirement  of  the  leather;  then 
dry  it.  Pommel  the  hair  side  in  the  same  manner  as 
before.  Pare  the  borders  upon  the  horse  with  the  round 
knife,  and  at  last  spread  over  it  a  light  coating  of  pure 
and  clear  oil. 


CHAPTER  CXXI. 

CALF-SKIN  LEATHER  FOR  BELTS. 

Cut  off  the  heads  and  extremities  of  the  skins,  soak 
them  in  a  tub  until  sufficiently  wet,  shave  them  upon 
the  horse  with  the  head-knife  until  equally  thick.  Beat 
them  in  a  trough  with  the  pestle,  dry  them,  and  grease 
them  slightly  upon  the  flesh  side  with  a  mixture  of 


GREASING  TANNED  HIDES. 


469 


equal  parts  of  tallow  and  oil,  and  on  the  hair  side  with 
linseed  oil  alone.  Then  dry  them  and  work  them  upon 
the  flesh  side  with  the  stretching  knife,  and  sleek  upon 
the  grain  with  the  glass.  Sometimes  a  grain  is  given  as 
above  described. 


CHAPTER  CXXII. 

GREASING  TANNED  HIDES:- 

Mr.  George  Huttelm  uer,  of  Alleghany,  Pennsylvania, 
has  invented  a  new  and  useful  improvement  in  the  pro¬ 
cess  of  greasing  tanned  hides,  and  patented  it  in  Septem¬ 
ber,  1863. 

In  the  process  of  greasing  tanned  leather,  it  is  required 
that  the  tallow  should  penetrate  it  thoroughly,  and,  in 
order  to  effect  this,  he  finds  it  very  desirable  to  expose 
the  leather  to  a  moist  heat,  sufficient  to  open  the  pores 
of  the  skin  and  to  keep  the  tallow  melted  during  the 
whole  process,  and  at  the  same  time  to  apply  friction  to 
the  leather  so  as  to  rub  the  grease  well  in.  Where  this 
operation  is  carried  on  by  hand,  as  is  usual,  it  is  obviously 
impossible  to  secure  all  these  conditions,  as  the  heat 
required  is  too  great,  and  even  if  the  tallow  be  melted 
and  sufficiently  heated  when  first  applied,  it  soon  becomes 
cool  when  exposed  to  the  external  air. 

His  invention,  then,  consists  in  applying  the  tallow  to 
the  tanned  hides  in  a  suitable  closed  vessel,  which  is 
previously  heated  by  steam,  and  which  will  retain  suffi¬ 
cient  heat  during  the  continuation  of  the  process  and 
simultaneously  applying  to  the  leather  a  constant  friction 
to  rub  in  the  melted  grease.  To  effect  this,  he  uses  the 
following  apparatus : — 

Fig.  145  is  an  end  view  or  elevation  of  the  apparatus. 

Fig.  146  is  a  side  view. 

Fig.  147  is  a  section  through  the  centre  of  tHe  appa¬ 
ratus,  in  the  plane  of  its  axis,  showing  the  construction 
of  the  interior. 

Fig.  148  is  a  transverse  section  of  one-half  of  the 
apparatus  at  right  angles  to  its  axis. 


470 


CURRYING. 


Pier-  145. 


In  the  several  figures,  like  letters  of  reference  desig¬ 
nate  similar  parts. 

The  apparatus  consists  of  a  large  cylindrical  wooden 
vessel,  which  should  not  be  less  than  ten  feet  in  diameter 
and  of  any  convenient  length,  although  its  dimensions 
may  be  varied  to  suit  any  desired  capacity.  This  vessel 
may  be  conveniently  made  like  a  barrel,  the  circum- 


GREASING  TANNED  HIDES. 


471 


Figr.  147. 


ference  being  constructed  of  wooden  staves,  g,  g,  about 
1  i  inch  in  thickness ;  these  staves  are  bound  together  by 
strong  iron  bands  or  hoops  i,  i,  surrounding  the-  vessel  at 
suitable  distances  apart ;  the  hands  or  end  pieces,  u,  of 
the  vessel  are  also  made  of  wood,  and  are  supported  by 
a  circular  iron  plate  6,  b,  in  the  centre  of  each’  end  piece, 
to  which  are  fastened  arms  rf,  d,  which  radiate  from  the 


472 


CURRYING. 


centre  of  plate  b,  b  ;  the  arms  are  fastened  to  the  central 
arm  plates  by  screws  c,  e,  and  the  end  pieces  are  like¬ 
wise  bolted  or  otherwise  fastened  to  the  arms  d,  d  ;  in 
one  of  the  end  pieces  is  a  door  f,  through  which  the 
tallow  and  leather  are  inserted  in  the  cylinder ;  from  the 
centre  of  each  ofthe  circular  iron  plates  6,  projects  a 
journal  k,  on  which  the  cylinder  revolves  in  suitable 
bearings  l ,  which  are  supported  by  the  framework  a ,  a, 
sustaining  the  entire  cylinder. 

Around  the  outside  of  the  cylinder,  at  any  convenient 
point  is  a  band  or  hoop  h,  furnished  with  cog-teeth, 
which  gear  into  a  pinion  g ,  to  which  motion  is  commu¬ 
nicated  from  the  steam  engine  or  other  primary  motion. 

Inside  the  cylinder,  the  staves  comprising  its  peri¬ 
phery  are  studded  with  a  number  of  pins  p,  p ,  projecting 
therefrom  and  pointing  towards  the  centre  of  the  cylin¬ 
der.  These  pins  should  be  about  two  inches  in  length, 
and  may  be  fastened  to  circular  ribs  m  attached  to  the 
staves  g ,  g. 

The  apparatus  thus  described  may  be  varied  in  size, 
shape,  or  construction,  so  that  the  designed  effect  is 
produced. 

Before  inserting  the  tallow  and  the  tanned  hides  into 
the  cylinder,  it  is  previously  heated  by  injecting  steam 
for  a  sufficient  length  of  time  to  make  the  staves  and 
ends  of  the  cylinder  so  hot  as  to  be  perceptibly  felt  from 
the  outside,  and  so  as  to  secure  a  temperature  in  the 
cylinder,  after  the  steam  is  allowed  to  escape,  of  about 
180°. 

The  injection  of  steam  is  then  discontinued,  and  any 
condensed  water  allowed  to  escape  at  the  door  f,  or 
other  aperture  for  that  purpose. 

The  tallow,  previously  melted  by  gentle  heat,  is  then 
poured  into  the  heated  cylinder,  and  the  tanned  hides, 
in  a  half  dry  state,  are  inserted  and  the  door  securely 
closed. 

The  proper  quantity  of  tallow  will  vary  according  to 
the  quality  and  kind  of  leather  to  be  greased,  but  one 
hundred  p$runds  of  calf-skins  will  require  about  10  lbs. 
of  tallow.  The  revolution  of  the  cylinder  is  then  com- 


SATURATION  OF  LEATHER  WITH  GREASE. 


473 


menced,  and  continued  for  two  or  three  hours  more  or 
less,  according  to  the  quality  and  quantity  of  the  leather 
inserted  therein,  care  being  taken  not  to  fill  the  cylin¬ 
der  so  full  of  hides  as  to  interfere  with  a  constant  and 
violent  motion  of  the  leather,  which  being  carried 
round  by  the  pins  p,  p,  should  be  able  to  fall  from  the 
top  of  the  cylinder  on  to  the  points  of  the  pins  at  the 
bottom. 

By  the  moist  heat  contained  in  the  cylinder,  the  pores 
of  the  leather  are  kept  open,  and  the  tallow  is  kept  so 
hot  as  to  enter  it  readily,  while  the  continued  rubbing 
of  the  hides  on  the  pins  causes  their  complete  saturation 
with  grease. 

Thus  by  means  of  the  combined  high  heat  and  con¬ 
stant  friction,  a  result  is  attained  far  superior  to  that 
which  is  accomplished  by  any  degree  of  heat  and  rubbing 
which  is  attainable  when  the  hides  are  greased  by  hand, 
or  in  vessels  not  so  heated. 

This  process  produces  a  very  durable,  solid  and  yet 
pliable  and  elastic  leather,  superior  in  these  respects  to 
that  made  in  the  ordinary  way.  Care  should  be  taken 
that  the  hides  are  of  a  uniform  degree  of  moisture,  com¬ 
monly  called  half  dry,  before  they  are  inserted  into  the 
cylinder ;  if  too  dry  in  spots,  they  should  be  wetted  in 
those  places  before  they  are  put  in,  otherwise  the  greas¬ 
ing  will  not  be  uniform.  The  leather  greased  by  this 
process  is  finished  in  the  usual  manner. 


CHAPTER  CXXIII. 

SATURATION  OF  LEATHER  WITH  GREASE. 

In  the  saturation  of  leather  with  grease,  a  very  faulty 
system  is  in  some  cases  followed,  from  its  being  believed 
that  leather  must  be  dry  in  order  to  absorb  the  grease, 
and  become  thereby  more  enduring  and  flexible.  Pre¬ 
cisely  the  contrary  of  this  is  the  fact.  However  incom¬ 
prehensible  it  may  appear  at  first  glance,  moist  leather 
combines  easier  with  oil  or  grease  than  dry.  This  seem¬ 
ing  paradox  is,  however,  easily  explained ;  dry  leather 


474 


CURRYING. 


is  drawn  closely  together,  its  pores  are  closed ;  and, 
therefore,  it  absorbs  fatty  bodies  only  slowly ;  moist 
leather,  on  the  contrary,  is  expanded  and  flexible,  and 
its  pores  are  open.  If  it  is  smeared  over  with  oil  or 
liquid  grease,  this  penetrates  the  pores  easily,  entering 
even  into  the  smallest  as  soon  as  the  water  disappears, 
and  its  evaporation  is  facilitated  by  the  opening  of  the 
pores  which  have  absorbed  the  oil.  It  is  easy  to  con¬ 
vince  one’s  self  of  this  effect  of  oil  upon  moist  leather. 

Take  a  small  piece  of  wet  leather,  or  a  wet  boot, 
place  it  in  a  warm  place  where  it  can  dry  slowly,  and  it 
will  become  quite  hard  and  brittle ;  but  if  you  smear  it 
with  oil  and  grease,  it  will  retain  its  pliability,  and  after 
being  thoroughly  dried,  it  will  not  have  been  in  the 
least  impaired.  Moist  leather  smeared  with  grease  may, 
therefore,  be  dried  by  heat  without  detriment.  If  dry 
leather  be  saturated  with  warm  grease,  the  durability  of 
the  leather  will  be  much  impaired,  because  the  heat 
c.ontracts  the  fibres,  and  the  oil  easily  acquires  such  a 
heat.  The  saturation  of  boot  soles,  as  well  as  the  rub¬ 
bing  in  of  sand  or  fine  iron  filings,  is  only  practicable 
when  the  shoemaker  turns  the  inner  or  flesh  side  of  the 
leather  outward.  This  possesses  also  another  advantage. 
The  flesh  side  has  wider  pores,  and  is  less  firm  than  the 
outer  side.  If  the  latter — the  outer  side — is  made  the 
outside  of  the  sole,  it  will  speedily  give  out,  as  soon  as 
the  hard  external  surface  is  worn  away,  for  the  sof£ 
inner  side  can  offer  no  further  resistance;  and,  moreover, 
it  does  not  absorb  the  grease  owing  to  the  smallness  and 
rigidity  of  the  external  pores.  If,  on  the  contrary,  the 
soft  side  is  turned  outward,  thfen  the  side  takes  in  a  con¬ 
siderable  quantity  of  wax,  grease,  and  oil,  and  it  will  be 
more  pliable  and  enduring ;  and  even  after  this  origi¬ 
nally  soft,  but  now  enduring  portion  has  been  worn  out, 
there  still  remains  the  hard  part,  the  outward  hide  side 
being  a  guard  sole,  which  can  be  worn  to  almost  the 
thinness  of  paper  without  giving  out.  The  most  en¬ 
during  soles  of  this  description  are  made  from  the  neck 
of  the  hide,  having  the  fleshy  side  outward,  and  properly 
impregnated  with  wax  and  grease.  The  only  fault  that 


CALF-SKINS  CALLED  ALUMED  SKINS. 


475 


they  have  is  this,  that  in  walking  upon  grass,  on  account 
of  their  smoothness,  you  are  apt  to  slip.;  but  soles  satu¬ 
rated  with  grease  are  not  only  softer  to  the  feet,  but 
cooler,  which  is  a  great  advantage  in  summer. 


CHAPTER  CXXIV. 

CALF-SKINS  CALLED  ALUMED  SKINS. 

These  skins  are  chiefly  employed  by  bookbinders. 
The  process  of  making  them  has  been  described  at  length 
by  De  La  Lande,  from  whose  work  we  extract  the  follow¬ 
ing  : — 

For  the  manufacture  of  this  leather  select  dry  skins 
of  stillborn  calves  or  others  of  low  price;  reject  those 
injured  by  weevils  or  worms.  When  you  open  them, 
beat  them  strongly  with  a  stick,  and  deposit  them  in  a 
place  not  too  warm  or  too  damp.  W ork  at  a  time  thir¬ 
teen  dozen  of  dry  skins.  Deposit  them  in  an  oval  pit, 
dug  out  in  the  ground  ;  this  pit  is  from  eleven  to  thirteen 
feet  long,  by  three  and  a  half  to  four  and  one-third  feet 
wide,  and  six  and  a  half  feet  deep.  Pass  the  water 
into  this  pit  by  an  oval  aperture,  one  and  a  half  feet  in 
height  and  narrow  enough  to  prevent  the  skins  escaping 
from  it,  and  draw  away  by  another  similar  opening. 

Leave  the  skins  in  the  pit  for  two  or  three  days  in 
summer  and  six  or  eight  in  winter.  Take  them  out, 
stack  them,  and  next  day  scrape  them  upon  the  horse 
with  a  blunt  knife.  Deposit  them  again  in  the  vat, 
leave  them  two  days,  scrape  them  as  before,  and  if  they 
are  not  sufficiently  soft,  expose  them  a  third  time  in  the 
pit  for  one  day  and  scrape  them.  Place  them  in  the 
lime  pit, •which  is  a  hole  about  five  feet  deep,  with  a  pro¬ 
portionate  breadth  and  length.  Into  this  pit  throw  from 
forty  to  fifty  buckets  of  water  and  a  cask  full  of  lime, 
which  is  left  to  slack  for  twelve  or  fifteen  hours.  Stir 
the  contents  of  the  pit  with  a  long  pole,  deposit  in  it 
the  skins  singly,  and  dip  them  with  a  stick.  Leave  in 
the  lime  pit  for  a  day,  take  out,  spread,  and  stack  them  ; 
pass  them  subsequently,  in  the  same  way,  through  new 


476 


CURRYING. 


lime  pits,  gradually  increasing  the  strength  until  the 
hair  is  ready  to  Jbe  removed.  Wash  them  well  in  run¬ 
ning  water,  depilate  and  deposit  them  again  in  a  vat 
similar  to  the  first  described ;  let  them  soak  one  night, 
being  kept  in  position  by  a  long  heavy  pole  placed  lon¬ 
gitudinally  above  them.  This  done,  the  skins  are  well 
fleshed  upon  the  horse  with  a  sharp  knife  until  the  flesh 
side  can  scarcely  be  distinguished  from  the  grain.  Thin 
down  the  necks  until  they  become  of  equal  thickness 
with  the  other  parts  of  the  skin.  Cut  off  the  ears,  tails, 
and  other  extremities,  and  use  them  to  make  glue. 
Return  the  skins  to  the  first  pit,  leave  them  over  night 
in  water,  and  work  the  hair  side  on  the  horse  to  expel 
the  lime.  After  this,  empty  three  or  four  bucketsful  of 
dogs’  or  chickens’  dung  into  a  large  vat  and  mix  it 
thoroughly  with  a  bucketful  of  water  by  stamping  upon 
the  mixture  with  the  feet.  Throw  cold  water  in  the 
vat  until  half  full,  and  mix  in  some  hot  water.  Throw 
the  skins  in,  and  stir  for  a  few  minutes  with  sticks,  draw 
the  liquor  into  a  boiler  and  heat  it,  and  the  skins,  after 
having  been  left  for  one  hour  are  arranged  in  a  corner 
of  the  vat,  and  kept  in  place  by  two  sticks  crossed  over 
each  other.  Pour  the  hot  liquor  in  the  empty  part  of  the 
vat,  a  bucketful  at  a  time,  stirring  all  the  time ;  mix  with 
the  cold  liquor  so  as  to  avoid  injuring  the  skins  by  scald¬ 
ing.  When  the  water  is  sufficiently  hot,  remove  the 
sticks,  and  stir  the  skins  around  in  the  vat  three  or  four 
times.  Return  the  liquor  to  the  boiler,  and  repeat  the 
same  operation,  being  careful  not  to  add  the  hot  water 
too  rapidly  to  the  contents  of  the  vat  and  to  try  its  tem¬ 
perature  frequently  with  the  hand.  Leave  the  skins  in 
for  half  an  hour. 

Collect  the  skins  in  a  corner  of  the  vat,  and  examine 
them ;  stretch  them  in  every  direction,  and  when  per¬ 
fectly  pliable  and  soft  they  are  ready  to  be  taken  out. 
At  first,  remove  one  or  two  dozen  of  those  most  ad¬ 
vanced  in  the  preparation,  deposit  them  in  buckets;  then 
empty  the  vat  of  water  as  before,  and  turn  the  skins  three 
or  four  times.  A  quarter  of  an  hour  after  fill  the  boiler 


CALF-SKINS  CALLED  ALUMED  SKINS. 


477 


again,  collect  the  skins  together;  take  out  more  of  them, 
and  so  on  until  they  are  all  removed. 

This  part  of  the  operation  must  be  done  very  carefully, 
for  if  the  skins  are  allowed  to  remain  in  the  hot  mixture 
after  reaching  the  proper  point,  they  are  rapidly  softened 
and  destroyed.  A  repetition  of  the  process  described, 
continued  for  six  or  seven  hours,  is  sometimes  necessary 
for  imparting  the  requisite  qualities  to  the  stronger  skins. 
Experience  alone  can  guide  to  determine  the  proper  time 
for  removing  them  from  the  vat.  When  this  is  done 
take  out  the  skins  from  the  vat ;  stretch  them  and  scrape 
them  upon  the  beam,  in  order  to  soften,  distend,  and 
clean  them ;  and  if  any  are  found  too  firm,  they  are 
replaced  in  the  vat  while  the  rest  are  washed.  Then, 
allow  the  contents  of  the  vat  to  escape  through  the 
bung-hole.  Wash  it  well,  and  fill  it  half  with  clear 
river  water  while  you  throw  in  a  basketful  of  fresh  tan. 
Wash  the  skins  and  stir  them  in  this  water  with  sticks, 
and  leave  in  the  vat  till  next  day.  Take  them  out ; 
drain  upon  planks,  and  transfer  them  to  the  care  of  the 
sempstress.  She  then  examines  every  skin,  and  closes 
any  holes  which  may  exist  in  them.  The  skins,  except¬ 
ing  the  tail  part,  are  then  sewed  with  the  flesh  side  out¬ 
wards  into  the  form  of  a  bottle.  For  this  purpose  she 
uses  a  large  needle,  flat  at  the  point,  and  with  a  double 
thick  thread,  stitches  one  part  of  the  skin  at  a  distance 
of  one-fifth  of  an  inch  from  the  edge,  and  the  other  that 
of  half  an  inch,  turning  over  the  latter  upon  the  former 
in  a  hem,  but  not  pressing  it  down  tightly  enough  to 
prevent  water  from  draining  through,  or  to  cause  the 
production  of  dark  spots  and  lines  after  tanning.  A 
workman  places  in  each  bag  a  quantity  of  tan  propor¬ 
tioned  to  its  size ;  after  which  the  sempstress  sews  up  the 
tail  part,  closed  by  the  hind  legs,  so  as  just  to  permit  the 
introduction  of  a  copper  socket  for  a  wooden  funnel. 
The  bags  are  then  brought  near  to  a  vat  in  which  the 
tanning  has  just  been  completed.  The  sacks  in  this  vat 
are  removed  to  a  rack  in  order  to  be  unripped.  The 
vat  is  left  half  full  of  the  old  liquor,  and  there  is  poured 


478 


CURRYING. 


into  it  a  quantity  of  hot  fresh  liquor,  sufficient  to  make 
the  contents  lukewarm. 

This  fresh  liquor  is  prepared  by  pouring  the  contents 
of  the  already  tanned  sacks  into  a  vat  provided  with  an 
upright  door  or  partition  at  one  end,  through  which  the 
liquor  which  has  drained  from  the  tan  passes,  and  col¬ 
lecting  in  the  empty  space  is  transferred  to  a  boiler. 
The  workman  then  takes  a  bag  of  skins,  and  empties 
into  it,  through  the  funnel,  a  small  bucketful  of  water, 
and  closes  the  mouth  by  tying  it  up  with  a  small  strip 
or  thong  which  had  been  previously  cut  from  the  skin 
for  the' purpose,  and  left  hanging  from  the  tail;  the  bags 
having  each  been  filled  with  the  same  quantity  of  water 
and  then  placed  in  the  vat,  and  left  for  an  hour,  while 
another  portion  of  liquor,  prepared  by  percolating  through 
tan,  is  being  heated  in  the  boiler.  The  workman  then 
places  the  bags  upon  a  rack  at  one  end  of  the  vat  into 
which  the  heated  water  has  been  poured,  fills  them  again 
through  the  funnel  from  his  little  bucket,  tying  them  as 
before,  by  which  they  are  made  to  assume  a  pyramidal 
shape  in  the  vats.  Repeat  this  operation  a  third  time 
at  the  expiration  of  one  hour,  increasing  the  heat  of  the 
liquor  as  before.  The  liquor  should  be  less  heated  for 
those  skins  which  have  been  a  long  time  in  the  lime-pits 
than  for  those  which  have  been  a  shorter  time,  but  the 
skill  exhibited  in  making  this  distinction  can  only  be 
acquired  by  long  experience.  Next  day  perforin  a 
similar  operation  in  a  third  vat,  while  the  bags  deposited 
the  day  before  are  left  to  soak  in  the  vat.  The  third 
day  take  out  the  skins  of  the  first  vat,  and  leave  to  drain 
upon  a  rack  placed  over  the  vat.  Throw  them  upon  the 
rack  in  the  vat,  upon  which  they  are  unripped  and 
emptied  of  their  tan.  Fold  them  with  the  flesh  side 
within,  and  wash  them  in  running  water;  place  them 
upon  a  trestle  to  drain;  open  them  at  the  hindquarters, 
and  hang  up  in  a  shed,  with  the  heads  down,  on  nails 
placed  some  distance  apart. 

When  dry,  pile  them  up,  and  leave  them  until  ready 
to  be  sent  to  market.  Then  moisten  them,  in  summer, 
by  exposure  to  the  dew  of  night  air;  tread  them  out  in 


jaekel’s  process. 


479 


order  to  render  them  supple  and  to  efface  the  marks  of 
the  sewing;  assort  them,  according  to  size,  into  packs  of 
six  each,  which  are  tied  together  by  the  heads  with  pack 
thread. 

Hog-skins  used  by  bookbinders  for  Bibles  and  church 
books,  are  prepared  in  the  same  manner  as  calf-skins, 
but  they  differ  from  them  in  being  exceedingly  thick 
and  strong. 

Tanned  sheep-skins,  used  by  bookbinders,  are  not 
alumed  as  calf-skins,  but  are  only  limed  and  tanned. 
Some  of  these  are  sewed  up  and  tanned  similarly  to  the 
calf-skins,  while  others  are  tanned  by  stratifying  them 
with  bark. 


CHAPTER,  CXXV. 

F.  JAHKEL’S  PROCESS  FOR  MANUFACTURING  LEATHER 
FOR  HARNESS-MAKERS. 

The  fine  brown  leather  made  in  England  for  saddlers’ 
uses  is  very  highly  esteemed,  and,  notwithstanding  its 
hi, uh  price,  is  much  sought  after,  being  superior  to  any 
other  in  suppleness,  density,  and  color. 

Its  excellence  is  not  attributable  to  any  novelty  in 
the  process  employed  in  its  manufacture,  or  to  the  use 
of  complicated  machinery,  but  solely  to  the  care  with 
which  the  materials  are  selected,  and  to  the  skilful  and 
accurate  manipulation  of  the  workman.  The  finest 
skins  used  for  this  leather  come  from  cattle  raised  in 
Wiltshire  and  Somersetshire,  the  climate  of  which  coun¬ 
ties  seems  to  be  the  best  adapted  to  secure  the  develop¬ 
ment  of  tissue  in  these  animals,  and  particularly  of  the 
firm,  elastic,  and  resisting  integuments,  which  are  so 
necessary  for  the  production  of  grain  leather. 

Skins  of  cows  or  of  young  bulls  are  preferred.  They 
are  usually  tanned  in  the  neighborhood  of  Bristol,  and 
sent  to  London,  where  the  best  are  selected  by  the  manu¬ 
facturers. 

The  processes  of  tanning  are  similar  to  those  elsewhere 
employed,  and  comprehend,  besides  liming  and  depilating, 


480 


CURRYING. 


the  use  of  grainiers  of  chickens’  or  pigeons’  dung,  dipping 
immersion  in  tan  baths  of  different  strengths,  and  two 
separate  tannings  in  pits  with  fresh  barks  of  the  finest 
quality.  The  currying  which  this  leather  undergoes 
serves  to  remove  its  original  dryness,  stiffness,  and  depth 
of  color,  and  to  render  it  supple,  elastic,  and  impervious 
to  moisture,  without  diminishing  the  solidity  and  density 
of  structure  given  to  it  by  the  tanning. 

At  first,  cut  the  leather  in  half  along  the  length  of  the 
skin,  and  repeatedly  soak  it;  beat  it,  and  wash  it  in  cold 
water  to  dissolve  and  remove  the  gallic  acid  and  ex¬ 
tractive  matter,  which,  if  allowed  to  remain,  might  by 
oxidation  deepen  the  color,  and  interfere  Avith  the  pro¬ 
per  absorption  of  the  substances  which  are  afterwards 
applied.  After  all  foreign  bodies  have  been  removed  by 
these  means,  the  skins,  although  saturated  with  tannin, 
are  yet  in  a  condition  which  enables  them  to  absorb 
sumach ;  and  accordingly  they  are  deposited  in  a  bath  con¬ 
taining  one-quarter  of  their  weight  of  powdered  sumach. 
Take  the  leather  out,  and  dip  it  again  in  a  new  position 
two  or  three  times  every  day  while  in  this  bath,  stirring 
every  time  the  powder  which  has  settled  to  the  bottom. 
At  the  end  of  the  second  day  add  a  quantity  of  sumach 
equal  to  that  already  used.  Take  the  skins  at  the  end 
of  three  days;  they  are  found  to  be  not  only  improved 
in  color,  but  more  soft  and  pliable  than  before  the  treat¬ 
ment.  To  more  completely  develop  the  lustre-like  yel¬ 
low  color  of  these  skins,  they  are  washed  in  water  to 
remove  the  sumach,  and  then  passed  repeatedly  through 
a  very  weak  bath  of  sulphuric  acid,  being  quickly  taken 
out  after  each  immersion,  and  immediately  rinsed  in 
pure  water  to  take  up  the  acid,  which,  if  allowed  to 
remain,  will  destroy  the  leather. 

Dry  the  leather ;  then  oil  it  upon  the  flesh  side  with 
pure  cod-liver  oil,  and  when  thoroughly  penetrated  by 
this,  oil  it  with  a  mixture  of  best  whale  oil  with  half 
its  weight  of  tallow  ;  in  the  meantime,  scraping  as  usual 
upon  the  grain  with  the  fleshing-knife.  Then  pare  it, 
sleek  and  beat  it  out  flat.  All  these  operations  are  per¬ 
formed  with  the  hand,  Avithout  the  help  of  any  ma- 


CURRYING  OF  GOAT-SKINS. 


481 


chinery.  The  excellence  of  the  products  depends  entirely 
upon  the  skill  and  attention  of  the  workman. 


CHAPTER  CXXVI. 

CURRYING  OF  GOAT-SKINS. 

The  preparation  of  these  skins,  on  account  of  their 
great  thinness,  requires  as  much  care  and  labor  as  calf¬ 
skins.  The  currier  receives  them  dried,  after  having 
been  oiled.  At  first  he  softens  them  by  soaking  for  24 
hours  in  a  vat  full  of  water ;  he  treads  them  out  under 
the  feet  three  at  a  time,  and  scrapes  them  upon  the 
flesh  side  with  a  blunt  knife.  When  nearly  dry,  he  oils 
them  with  a  mixture  of  train  and  scouring  oil.  A 
dozen  of  skins  weighing  from  18  to  20  lbs.  requires 
from  6  to  8  lbs.  of  oil.  The  oiling  being  completed,  he 
again  treads  them  out,  scrapes  clean  and  pommels  with 
instruments  smaller  than  those  used  for  calf-skin.  To 
free  the  surface  of  the  excess  of  oil,  and  to  soften  and 
brighten  them,  he  dissolves  four  ounces  of  potash  in 
two  bucketsful  of  water,  and  passes  lightly  the  solu¬ 
tion  over  the  grain  side,  the  saponaceous  compound 
which  it  forms  is  wiped  off.  The  above  quantity  of 
potash  is  sufficient  for  six  dozen  of  skins. 

After  this  operation,  grain  the  leather  with  the  pom¬ 
mel,  and  rub  it  with  a  bunch  of  straw  to  soften  the 
grain.  Wipe  it  well  with  a  woollen  rag,  and  black  it 
with  the  following  mixture:  6ne  ounce  powdered  nut- 
galls,  onof  pound  copperas,  and  a  handful  of  Brazil 
wood;  the  whole  is  boiled  some  time  in  a  little  porter 
and  then  stirred  in  a  bucketful  of  the  same  liquid. 
Black  six  skins  at  a  time,  and  then  pile  them  upon  each 
other  on  the  table  or  floor.  Then  turn  the  pile,  so  that 
those  which  have  been  blackened  first  become  upper¬ 
most,  and  wipe  thoroughly  each  one  with  a  woollen  rag, 
and  stretch  them  to  dry.  When  the  skins  are  partially 
dried,  black  them  a  second  time  with  a  hard  brush,  dis¬ 
tribute  the  color  over  the  surface  rapidly  and  uniformly, 
then  wipe  them  with  a  roller  made  of  blanket  stuff,  and 
31 


482 


CURRYING. 


dry  them  in  the  air.  Pommel  them  now  across  the 
grain,  wipe,  moisten  with  sour  beer  applied  upon  a 
piece  of  listing,  and  rub  with  a  bunch  of  straw  to 
reduce  the  grain. 

This  operation  done,  trim  the  borders  upon  the  horse, 
pare  the  skins  with  the  round-knife,  pommel  and  brighten 
with  barberry  juice.  This  last  operation  must  be  done 
carefully,  and  is  performed  by  passing  the  listing,  dipped 
in  the  polish,  rapidly  and  lightly  over  the  surface  from 
head  to  tail  and  across,  continuing  to  rub  while  the  rag 
remains  moist  and  until  a  polish  is  given.  Then  apply 
the  roller  equally  and  forcibly  to  the  whole  surface  from 
head  to  tail,  pommel  the  skin  lengthwise  and  across,  and 
dress  upon  the  grain  with  pure  linseed  oil. 

Formerly  it  was  the  fashion  to  form  a  diamond  grain 
surface  upon  goat-skins,  but  now  they  are  grained  in 
straight  parallel  ridges,  formed  by  pommelling  from 
head  to  tail  alone. 

We  will  now  describe  another  mode  of  preparing 
goat-skins  indicated  by  M.  Dessables : — 

Sprinkle  two  skins  at  a  time,  upon  the  hair  side,  with 
water  from  a  brush,  and  place  them  upon  each  other 
with  their  hair  sides  in  contact,  and  fold  them  up  into 
a  cap-like  form,  beat  them  with  the  feet  or  the  mace. 

Pommel  them  from  head  to  tail  and  crosswise,  slightly 
moistening  them  at  the  same  time  with  water.  After 
you  have  prepared  a  dozen  or  more  skins  in  this  way, 
place  them  in  a  tub  with  a  sufficient  quantity  of  water 
to  cover  them,  beat  them  with  the  rammer,  stretch  out 
and  smooth  them  upon  the  marble  with  a  stretching 
iron,  and  dry  partially.  Then  wash  the  hair  side  over 
with  a  weak  solution  of  potash,  scrape  the  skins  upon 
the  flesh  with  the  stretcher,  rub  over  with  a  bunch  of 
straw,  stretch  again  and  wipe  with  a  piece  of  woollen 
cloth  before  blacking.  The  color  is  prepared  as  in  the 
other  process.  Spread  this  blacking  lightly  with  a  brush 
over  the  hair  sides,  and  dry. 

Sometimes  instead  of  pure  water  a  solution  of  potash 
is  used  to  moisten  the  skins. 

When  dry,  apply  to  the  skins  a  second  coating  of 


PROCESS  OF  MANUFACTURING  RUSSIA  LEATHER.  483 

color  with  a  hard  brush  made  of  hog’s  bristles,  pass  it 
rapidly  over  the  surface,  and  press  upon  them  with 
considerable  force.  Then  wipe  the  hair  side  with  a 
woollen  cloth  made  into  the  form  of  a  roller,  and 
pommel  lengthwise. 

Pare  the  edges  with  the  head-knife,  scrape  the  leather 
and  wipe  it  again,  and  at  "last  pommel  so  as  to  produce 
quadrilateral  figures.  Polish  the  blackened  surfaces  by 
rubbing  them  with  a  piece  of  cloth  dipped  in  barberry 
juice,  smooth  with  the  roller,  and  oil  upon  the  hair  side 
with  linseed  oil ;  this  completes  the  operation. 


SECTION  IX. 

RUSSIA  LEATHER. 

The  Russians  have  manufactured  for  a"  long  time  a 
variety  of  fancy  red  leather  called  by  them  Juncten. 
rUhis  leather  has  an  agreeable  and  characteristic  odor, 
does  not  mould  even  in  damp  places,  and  is  not  attacked 
by  insects.  This  process  was  described  by  Pallas  and 
by  Fischertrcem,  and  a  factory  was  established  in  Prance 
at  St.  Germain  more  than  70  years  ago,  under  the  aus¬ 
pices  of  M.  Feybert,  but  did  not  prove  successful. 

The  process  we  are  going  to  describe  is  taken  from 
the  prize  work  on  the  subject  by  Grouvelle  and  Duval- 
Duval,  and  of  Mr.  Payen,*  but  all  these  methods  are 
defective,  and  the  Russian  process  is  not  yet  entirely 
known. 


CHAPTER  CXXVII. 

PROCESS  OF  MANUFACTURING  RUSSIA  LEATHER. 

Calf-skins  and  goat-skins  dyed  generally  of  a  red 
color,  cylindered  and  impregnated  with  a  purified  em- 
pyreumatic  oil  obtained  from  the  birch  tree,  constitute 


*  Dictionnaire  technologiqne. 


484 


RUSSIA  LEATHER. 


Russia  leather  For  this  object  select  the  whitest  and 
most  perfect  skins.  Deprive  them  of  hair  by  steeping 
them  in  a  mixture  of  ash  lye  and  quicklime  made  too 
weak  to  act  on  the  fibres.  Rinse ;  full  them  a  longer 
or  shorter  time,  according  to  their  nature ;  wash  in  hot 
water,  and  ferment  in  a  proper  steep.  Leave  eight 
days;  take  out;  full  again;  steep  a  second  time  if  ne¬ 
cessary  to  open  their  pores ;  clean  with  the  flesh  knife 
on  both  sides. 

For  200  skins  make  a  paste  with  38  lbs.  of  rye  flour 
fermented  with  leaven  ;  work  the  dough  with  a  sufficient 
quantity  of  water  to  form  a  bath  for  the  skins ;  soak 
them  forty-eight  hours;  transfer  them  to  small  pits;  let 
them  remain  fifteen  days ;  wash  them  well.  This  pre¬ 
liminary  operation  serves  to  prepare  the  skins  for  their 
uniform  and  complete  combination  with  tannin  and  ex¬ 
tractive  matter. 

Then  make  a  decoction  of  willow  bark,  and  when  the 
temperature  is  sufficiently  lowered  to  prevent  it  from 
injuring  the  fibres,  immerse  the  skins  in  it;  handle  and 
work  them  for  half  an  hour.  Repeat  this  operation 
twice  daily  during  a  week,  after  which  prepare  a  fresh 
decoction,  and  submit  the  skins  to  the  same  treatment 
for  another  week.  Then  dry  them  in  the  air  and  they 
are  ready  to  be  dried  and  dressed  with  the  oil. 

Dessables  has  given  another  method  of  preparing  the 
skins  for  the  chief  operation. 

Select  the  whitest  and  most  perfect  skins ;  soak  them 
in  water ;  scrape  them  upon  the  beam  ;  full  them  ;  work 
with  the  pommel,  and  then  oil  them  upon  the  flesh  side 
with  pure  fish  oil  and  upon  the  hair  side  with  train  oil 
scouring.  Dry  them  ;  pommel  them  again  ;  wash  over 
the  hair  side  with  a  solution  of  alum,  and  then  press 
under  the  cylinder.  This  cylinder,  by  which  the  dia¬ 
mond-shaped  grain  is  given  to  Russia  leather,  is  made 
of  steel,  12£  inches  long,  and  3  inches  in  diameter,  and 
is  covered  with  a  number  of  closed  parallel  threads  or 
grooves  like  those  of  a  screw,  but  cut  perpendicular  to 
its  axis  and  not  spirally.  This  cylinder  is  filled  with 
stone  weighing  from  300  to  400  lbs.  It  is  moved  in  two 


PROCESS  OF  MANUFACTURING  RUSSIA  LEATHER.  485 

directions  upon  a  wooden  bench,  by  means  of  a  cord 
passing  round  a  wooden  roller  with  a  handle ;  this  cord 
also  passes  over  two  cylinders  attached  to  the  floor  and 
a  fourth  one  upon  the  end  of  the  bench.  The  cylinder 
having  the  handle  upon  its  axle  is  divided  into  two  dif¬ 
ferent  parts,  over  which  the  two  extremities  of  the  cord 
pass  in  different  directions,  so  that  two  opposite  move¬ 
ments  can  be  given  to  the  cylinder  by  one  handle.  The 
cylinder  is  sustained  and  directed  by  iron  bars  placed 
along  the  bench  upon  which  it  rolls.  The  skin  which 
is  to  be  grained  is  placed  below  it  lengthwise  upon  the 
bench,  and  longitudinal  grooves  are  impressed  upon  its 
surface  by  the  track  of  the  cylinder.  The  skin  is  then 
removed,  and  again  placed  upon  the  bench,  either  cross¬ 
wise  or  at  an  angle,  according  as  it  is  intended  to  give 
it  a  square  or  diamond-shaped  grain. 

When  the  skins  are  properly  grained,  apply  to  them 
a  second  coat  of  alum  water,  and  when  nearly  dry  spread 
over  the  hair  side  the  Russian  oil ,  and  give  the  black  or 
red  color.  Then  expose  the  skin  repeatedly  for  a  short 
time  to  the  direct  rays  of  a  hot  sun,  until  the  color  has 
sufficiently  penetrated  its  substance  ;  then  full ;  pommel ; 
sleek  with  a  round  knife  upon  the  beam ;  and  at  last 
rub  well  upon  the  hair  side  with  a  hard  brush. 

The  principal  characteristic  of  the  preparation  of  Rus¬ 
sia  leather  is  its  impregnation  with  birch-bark  oil,  the 
fabrication  of  which  is  still  in  a  measure  kept  secret. 
In  order  that  the  oil  should  penetrate  the  leather  pro¬ 
perly  the  latter  must  not  be  either  too  moist  or  too  dry, 
but  should  contain  just  sufficient  water  to  enable  the  oil 
to  be  spread  equally  over  the  surface,  and  to  be  absorbed 
in  proportion  as  the  moisture  gradually  evaporates.  The 
leather  thus  prepared  retains  the  characteristic  odor  for 
a  long  time.  You  must  be  careful  not  to  apply  too  much 
of  the  oil,  for  fear  of  its  passing  through  and  staining 
the  grain  side.  To  fully  impregnate  a  large  cow-skin, 
from  twelve  to  sixteen  ounces  are  sufficient.  In  case 
the  leather  is  not  dyed,  or  of  morocco  to  which  you 
wish  to  impart  the  odor,  only  a  very  small  portion  should 
be  applied  to  the  flesh  side. 


486 


RUSSIA  LEATHER. 


The  composition  of  the  red  color  of  Russian  leather 
has  not  been  accurately  ascertained.  It  usually  contains 
Brazil  wood,  alum,  and  some  other  substances.  It  is 
not  very  durable,  and  does  not  resist  the  action  of  boil¬ 
ing  water  or  of  potash,  but  remains  unaltered  in  the  air. 
Other  dyes  of  better  quality  are  sometimes  used  which 
enhance  the  price  of  the  leather.  Black  Russia  leather 
is  prepared  in  the  same  way  as  the  other,  and  is  stained 
by  the  repeated  action  of  acetate  of  iron. 


CHAPTER  C  XXV  II I. 

DISTILLATION  OF  THE  EMPYREUMATIC  OIL  OF  BIRCH- 
TREE  BARK  FOR  RUSSIA  LEATHER. 

Much  attention  has  been  bestowed  upon  the  manufac¬ 
ture  of  the  empyreumatic  oil  of  birch  bark,  and  quite  a 
number  of  different  modes  of  preparing  it  have  been  de¬ 
scribed;  we  shall  give  the  most  important.  , 

Fischerstroeni’s  Process. — Separate  very  carefully  the 
whitish  membranous  epidermis  of  the  birch  from  all 
woody  matter.  Introduce  it  into  an  iron  boiler,  which, 
Avhen  full,  is  covered  with  a  vaulted  iron  lid,  from  the 
centre  of  which  issues  an  iron  pipe.  Place  over  this 
boiler  another  one,  into  which  this  tube  enters  without 
touching  its  bottom.  Bolt  the  edges  together  and  lute 
tightly.  Invert  them  so  that  the  one  containing  the 
bark  is  uppermost.  Sink  in  the  earth  the  lower  half  of 
this  apparatus,  cover  over  the  surface  of  the  upper 
boiler  with  a  lute  composed  of  clay  and  sand,  then  sur¬ 
round  it  with  a  wood  fire,  and  expose  to  a  red  heat 
until  the  completion  of  the  distillation.  As  soon  as  the 
boilers  are  cooled,  disconnect  them.  In  the  upper  one 
you  find  a  light  charcoal  powder,  and  in  the  under  one, 
used  as  a  receiver,  is  a  brown  oil,  odoriferous,  empyreu¬ 
matic,  mixed  with  tar  and  pyroligneous  acid.  Separate 
the  oil  from  the  other  substances  and  keep  it  in  a  close 
vessel. 

Another  Process. — Introduce  the  dark  birch  bark  into 
a  large  earthen  pot,  having  a  hole  in  the  bottom.  When 


DISTILLATION  OF  THE  EMPYREUMATIC  OIL. 


487 


the  pit  is  full,  set  the  bark  on  fire ;  over  that  pot  invert 
another  similar  pot  with  a  hole  for  the  escape  of  smoke, 
and  this  latter  is  placed  upon  a  bucket,  into  which  the 
tar  and  oily  matters  drop  as  they  are  formed. 

If  the  preparation  is  made  in  the  spring,  some  manu¬ 
facturers  mix  the  young  branches  of  birch  covered  with 
buds  with  the  bark.  This  arrangement  facilitates  the 
separation  of  the  oil,  which,  when  thus  prepared,  is  of 
a  lighter  color,  from  the  smaller  quantity  of  soot  it  con¬ 
tains. 

Grouvelle  and  Duval-DuvaT s  Process. — They  take  the 
white  epidermis  of  the  birch  bark,  well  separated  from 
all  ligneous  matters,  and  introduce  it  into  a  copper  still, 
similar  to  those  used  to  distil  wood  to  manufacture 
pyroligneous  acid.  They  adapt  to  it  a  receiver  immersed 
in  water,  in  which  the  gaseous  products  are  condensed. 
As  in  the  fabrication  of  pyroligneous  acids,  the  resulting 
products  are  pyroligneous  acid,  tar  in  larger  quantity,  and 
the  empyreumatic  oil  more  colored  and  less  abundant. 
This  oil  is  obtained  nearly  colorless  by  rectification,  but 
this  rectification  is  not  useful  except  in  case  the  oil  has 
to  be  used  for  skins  very  lightly  colored. 

Payen’s  Process. — By  repeating  the  distillation  per 
descensum  of  the  epidermis  of  the  birch  bark,  Mr.  Payen 
has  ascertained  that  with  a  very  simple  apparatus,  it  is 
possible  to  obtain  an  oil  less  colored  and  in  the  propor¬ 
tion  of  one-fifth  more,  at  a  temperature  less  elevated. 

His  apparatus,  represented  on  p.488,  is  thus  formed: — 

A  hole  is  made  in  the  bottom  of  an  earthen  furnace 
A,  large  enough  to  receive  the  neck  of  a  matrass  M. 
The  furnace  is  supported  by  two  bricks  placed  upon  the 
plank,  which  is  also  perforated  so  as  to  admit  of  the 
passage  of  the  neck  of  the  matrass,  and  which  rests 
upon  the  trestles  C,  C.  The  matrass  is  filled  to  its  utmost 
capacity  with  the  epidermis  of  birch  bark;  it  is  inverted 
and  passed  through  the  furnace  and  the  board.  Then 
the  neck  is  luted  and  placed  in  the  position  seen  in  the 
figure,  being  supported  by  sand  thrown  into  the  bottom 
of  the  furnace  us  high  as  F,  F ;  and  in  order  to  expose 
the  matrass  to  a  uniform  heat,  it  is  protected  by  inverting 


488 


RUSSIA  LEATHER. 


Fig.  149. 


over  it  an  earthern  hemispherical  vessel  or  crucible. 
Around  this,  burning  coals  are  placed,  and  the  fire  is 
kept  up  through  two  lateral  openings  D,  D,  the  dome  I, 
Iv,  L,  being  placed  upon  the  furnace  top.  Condensed 
water  first  trickles  from  the  mouth  of  the  matrass  into  a 
vessel  placed  beneath,  and  this  is  succeeded  by  drops,  and 
then  by  a  constant  stream  of  an  amber  colored  oil.  After 
a  time  this  ceases,  and  it  is  necessary  to  apply  heat  lower 
down  to  the  neck  of  the  matrass,  so  as  to  cause  the  dis¬ 
charge  of  the  last  portions  of  all  tarry  matters  which 
have  condensed  in  it. 

The  products  obtained  by  the  distillation  of  100  parts 
are  as  follows — 

A  brown  oily  matter,  light  fluid  empyreumatic,  solu¬ 


ble  in  ether  .......  70.00 

Thick  dark  brown  tar  containing  a  little  oil  .  .  5.00 

Water  acidulated  with  pyroligueous  acid  .  .  10.00 

Light  spongy  charcoal  .....  12.50 

Gases . 2.50 


100.00 

This  oil  may  be  readily  obtained  by  distilling  the 
bark  in  iron  cylinders  placed  horizontally  in  a  furnace 
similarly  to  gas  retorts. 


PREPARATION  OF  RUSSIA  LEATHER. 


489 


CHAPTER  CXXIX. 

NATURE  OF  THE  ODORIFEROUS  SUBSTANCE  OF  THE 
BIRCH-TREE  BARK. 

Messrs.  Paten  and  Chevalier  have  examined  the 
odoriferous  substance  of  the  epidermis  of  the  birch-tree. 
This  epidermis  contains  from  0.2  to  0.3  of  an  imme¬ 
diate  peculiar  principle,  white,  pulverulent,  soluble  in 
alcohol,  volatile.  Thrown  on  incandescent  charcoal  it 
exhales  abundant  vapors,  whitish,  with  an  aromatic 
odor,  sweeter  than  that  of  Russia  leather.  It  is  to  this 
principle,  called  Betuline  by  Mr.  Chevreul,  who  disco¬ 
vered  it  first,  that  are  due  the  characters  proper  to  Rus¬ 
sia  leather.  This  principle  can  be  assimilated  to  an 
insipid,  odorless  and  colorless  resin.  By  alteration  it 
acquires  a  very  fully  developed  odor.  It  is  probable 
that  by  the  distillation  per  descensum  a  greater  portion 
of  betuline  is  carried  away  without  alteration  and  in 
the  fluid  part.  It  is  possible  that  in  this  state  it  con¬ 
tributes  more  efficaciously  to  the  preservation  of  objects 
which  are  impregnated  by  it,  a  property  which,  as  every 
one  knows,  is  common,  1st,  to  resinous  bodies  not  to  be 
penetrated  by  dampness ;  2d,  to  many  volatile  oils  and 
odoriferous  substances,  to  preserve  vegetable  and  animal 
substances  subject  to  spontaneous  alteration. 


CHAPTER  CXXX. 

PREPARATION  OF  RUSSIA  LEATHER. 

Macerate  calf-skins  in  a  weak  alkaline  liquor,  work 
them  on  the  beam  and  wash  them  in  water,  dip  them  in 
a  mixture  of  water  and  oatmeal,  and  keep  them  in  till 
a  light  fermentation  is  established.  Birch-tree  bark  is 
preferable  to  oak  bark.  Stir  all  the  time.  The  tanned 
skins  are  rendered  supple  by  means  of  the  oil ;  they 
are  then  rubbed  several  times  with  the  tar  of  birch 
tree  bark;  they  owe  their  agreeable  odor  to  this  sub- 


490 


RUSSIA  LEATHER. 


stance.  Russia  leather  retains  that  odor  for  several 
years. 

This  leather  is  blackened  by  rubbing  it  after  tanning 
with  pyrolignite  of  iron.  In  Astracan  they  prepare  a 
very  tine  leather  with  elk  or  goat-skins.  The  operation 
is  similar  to  that  operated  on  sheep  skins.  •  The  leather 
is  left  for  three  days  in  a  bath  of  fermented  bran.  Spread 
each  skin  in  a  bucketful  of  water  containing  a  certain 
proportion  of  honey ;  it  is  passed  afterwards  in  a  sour 
bath  and  then  dried.  This  leather  is  dyed  red  by  im¬ 
mersing  it  in  a  bath  of  cochineal  containing  an  alkaline 
plant.  It  is  then  passed  in  a  solution  of  alum  and 
tanned.  The  red  can  be  made  brighter  and  more  solid 
by  using  nutgalls  instead  of  sumach.  The  yellow'  is  ob¬ 
tained  with  the  wild  chamomile. 


CHAPTER  CXXXI. 

COLORING  OF  RED  RUSSIA  LEATHER. 

Mr.  Jno.  Wagmijster,  a  tanner  of  Paggstall,  has  suc¬ 
cessfully  imitated  Russia  leather  by  employing  the  red 
dyed  cow-leather.  He  operates  as  follows:  As  a  basis, 
take  5  ounces  of  nitric  acid  and  heat  it  in  a  glazed  vessel 
in  a  chimney  flue,  but  not  over  an  open  fire,  until  it 
begins  to  smoke,  that  is,  until  a  red  fetid  vapor  rises; 
which  great  care  should  be  taken  not  to  inhale.  Then 
pour  it  over  one  pound  of  salt  of  tin  and  stir  it  with  a 
long  wooden  stick.  It  is  preferable  to  mix  the  salt  of 
tin  and  the  warm  acid  in  the  open  air,  or  in  a  strong 
draught,  so  as  not  to  be  too  much  exposed  to  the  danger 
of  inhaling  the  vapor.  The  stirring  with  the  skin  should 
be  carefully  continued  as  long  as  the  red  vapor  rises; 
but  as  soon  as  white  vapors  commence  to  ascend,  one- 
quarter  of  a  pound  of  hydrochloric  acid  should  be  poured 
into  the  mass,  stirring  it  briskly  all  the  while.  After  a 
few  minutes  pour  the  liquid  into  the  bottle  and  keep  it 
for  use.  In  filling  the  bottles  care  should  be  taken  not 
to  have  the  liquid  too  hot,  or  a  bottle  may  easily  burst 
and  hurt  the  operator. 


* 


COLORING  OF  RED  RUSSIA  LEATHER.  491 

The  liquor  until  used  should  be  kept  in  a  place  where 
the  temperature  is  moderate,  and  in  using  it,  from  twelve 
to  fifteen  times  its  volume  of  clean  water  should  be  added 
to  dilute  it. 

After  being  thoroughly  tanned  and  well  washed,  hides 
may  be  grained  with  this,  that  is  to  say,  this  corrosive 
substance  may  be  well  rubbed  in  by  means  of  a  brush. 
For  the  dye  take  1  lb.  Brazil  wood,  and  boil  it  an  hour 
in  six  quarts  of  clean  river  water.  Then  the  limpid  color¬ 
ing  liquor  must  be  strained  off  and  three-quarters  of  an 
ounce  of  cream  of  tartar  dissolved  in  it.  The  coloring  liquid 
with  the  tartar  should  be  well  boiled  together  for  an  hour. 
It  is  advisable  to  boil  the  coloring  liquid  separately  several 
days  before  the  tartar  is  added,  as  its  strength  will  be 
increased  thereby. 

As  in  black  dyeing  the  hides  should  be  smeared  only 
on  the  flesh  side,  then  fulled  and  wiped  off  with  woollen 
rags,  so  that  the  half-moist  condition  may  leave  the 
grain  open.  After  the  hide  is  thoroughly  dry,  it  should 
be  crimped  and  well  rubbed  two  or  three  times  with  the 
above-mentioned  corrosive  liquid,  and  then  spread  over 
also  two  or  three  times  with  the  warm  dyeing  liquor;  if 
cold,  warm  it.  In  the  preparatory  operation  as  well  as 
in  the  stirring,  brushes  should  be  used.  The  brush 
should  not  be  dipped  in  the  liquor,  but  the  liquor  poured 
upon  the  hide  and  the  brush  work  begun  at  once  in 
order  to  spread  the  stuff  uniformly,  and  that  the  stained 
hide  may  show  an  even  tone  of  color  in  all  parts.  The 
dye  must  be  applied  immediately  after  the  first  rubbing, 
because  it  is  then  moist  and  the  color  takes  better  and 
no  small  spots  are  left.  Therefore  it  is  better  that  two 
men  should  be  used  in  this  operation,  each  of  whom 
dyes  half  a  hide,  both  working  together,  thus  the  dyeing 
of  one  side  and  the  staining  of  the  other  side  will  go  on 
together.  Should  the  color  not  take  uniformly,  the  light 
spots  must  be  gone  over  again  with  the  dye. 

This  red  dye  is  very  lasting,  and  endures  as  long  as 
the  hide  itself,  so  that  hides  treated  with  this  prepara¬ 
tion  may  be  kept  on  hand  in  the  storehouse  for  further 
dressing.  Hides  that  have  been  coated  and  long  kept 


492 


RUSSIA  LEATHER. 


on  hand  dye  badly;  such  should  be  soaked  in  luke-warm 
water,  and  then  treated  like  fresh-tanned  hides. 

As  a  last  process,  the  stained  leather  should  be  moist¬ 
ened  on  the  flesh  side  with  tan  liquor,  sleeked,  dried,  and 
then  grained  and  crimped;  a  handsome  appearance  may 
be  given  to  that  leather  by  going  over  the  colored  side 
with  lime  water  by  means  of  a  sponge;  the  color  receives 
a  fine  gloss  and  a  peculiar  fiery  tint;  but  the  lime  water 
should  not  be  too  strong. 

CHAPTER  CXXXII. 

EXTRACT  FROM  A  MEMOIR  ON  THE  PROCESS  OF  TANNING 
SKINS  IN  RUSSIA  BY  THE  COUNT  OF  KARTSOFF* 

The  principal  Russian  manufactories  are  situated  in  the 
government  of  Misnie,  Novogorod,  Orlow,  Moscow,  Perm, 
Courks,  and  Wladimir.  The  city  of  Cazan  possesses  a 
very  extensive  establishment,  but  as  it  belongs  to  the 
government  the  products  manufactured  there  are  re¬ 
served  for  use  of  the  navy.  As  for  goat  and  sheep-skins 
proper  for  the  fabrication  of  morocco,  Cazan  exclusively 
manufactures  them. 

The  Tartars  are  the  principal  workmen  in  these 
shops.  Their  process  of  preparing  goat-skins  differs 
from  the  other  in  this :  that  they  use  sour  mares’  milk, 
into  which  they  pass  the  skins  after  the  raising.  It  is 
this  preparation  which  gives  to  the  morocco  the  supple¬ 
ness  which  distinguishes  it,  and  renders  it  proper  for 
the  different  uses  to  which  it  is  intended. 

When  the  skins  are  dried,  soak  them  in  water  to  soften 
them ;  the  degree  of  dryness  and  the  temperature  deter¬ 
mine  the  time  of  this  operation.  In  summer  they  are 
left  in  water  about  five  or  six  days,  and  in  winter  from 
ten  to  twelve  days. 

The  skins  are  washed  to  free  them  from  the  blood  and 
impurities  adhering  to  the  surface ;  for  this  purpose 
spread  them  and  raise  them  as  follows: — 

*  Bulletin  de  la  Societe  d’encouragement  de  l’industrie  nationale, 
vol.  xii.  page  211. 


PROCESS  OF  TANNING  SKINS  IN  RUSSIA. 


493 


Throw  the  skins  in  water,  to  which  some  hydrate  of 
lime  has  been  previously  added,  and  let  them  stay  in  the 
vats  a  longer  or  shorter  time  according  to  the  strength 
of  the  milk  of  lime.  Begin  at  first  to  put  160  lbs.  of 
lime  in  each  vat,  and  when  the  liquor  weakens  introduce 
a  new  quantity  of  lime.  The  vats  are  built  of  pine 
wood ;  they  are  8  feet  in  diameter,  and  6|  feet  in  height. 
They  are  hooped  with  iron,  and  are  sunk  a  few  inches 
below  the  floor  of  the  shop,  so  as  to  enable  them  to  be 
covered  with  planks. 

For  heavy  leathers  another  method  is  followed :  They 
are  carried  in  an  oven,  and  are  spread  one  on  the  other, 
covering  them  with  earth  to  prevent  fermentation.  A 
sour  bath  prepared  with  rye  bran  is  sometimes  used, 
principally  for  thin  skins. 

The  skins  are  inspected  several  times  a  day,  to  ascer¬ 
tain  when  the  hair  begins  to  loosen.  Take  it  off  then 
with  the  epidermis,  by  working  the  skins  on  the  horse 
with  a  two-handled  knife ;  then  equalize  the  inside  sur¬ 
face  with  a  knife. 

To  destroy  the  lime  which  has  penetrated  the  skins, 
wash  them  several  times.  For  this  purpose  a  man  in¬ 
troduces  them  one  after  the  other  into  a  vat,  and  beats 
them  with  the  feet  in  turning  them  ;  he  soaks  them  with 
warm  water  till  this  water  is  clear ;  then  he  washes 
them,  and  lets  them  soak  one  or  two  days  in  running 
water. 

To  this  operation  follows  the  tanning  ;  but  to  have 
the  tannin  penetrate  the  skins,  their  pores  are  opened 
by  swelling  them  ;  for  this  purpose  they  are  dipped  in 
an  acid  liquor  prepared  with  flour.  For  a  vat  of  the 
size  described  above,  they  use  sometimes  1000  lbs.  of 
rye  flour  and  from  4  to  6  lbs.  of  salt  dissolved  in  warm 
water ;  sometimes  2000  lbs.  of  oatmeal,  6  lbs.  of  salt, 
and  a  little  yeast.  In  some  places  they  use  spent  tan. 
When  the  acid  fermentation  is  established,  put  the  skins 
in,  and  leave  them  about  forty-eight  hours.  Sixteen 
pounds  of  flour  are  used  for  a  skin  of  an  ordinary  size. 

The  skins  thus  disposed  are  exposed  to  the  action  of 
a  weak  infusion  of  oak  bark  or  willow.  Then  they  are 


494 


RUSSIA  LEATHER. 


spread  on  a  wooden  grate  above  the  bark.  They  are 
piled  up,  and  covered  with  bark,  coarsely  ground  ;  and, 
as  you  raise  the  pile,  force  the  grate  down  the  pit  until 
it  reaches  the  bottom,  which  is  covered  with  a  bed  of 
the  same  bark.  The  pit  being  full,  water  the  skins  with 
spent  liquor.  They  are  covered  with  planks  loaded  with 
stones.  Leave  the  whole  from  fifteen  to  eighteen  days ; 
raise  the  skins,  and  change  the  bark.  Repeat  this  ope¬ 
ration  three  and  even  six  times  according  to  the  nature 
of  the  leather. 

When  tanned,  the  leather  acquires  a  certain  stiffness, 
which  is  corrected  by  dipping  it  from  twenty- four  to 
thirty-eight  hours  in  a  liquor  composed  of  120  lbs.  of 
oatmeal  and  8  lbs.  of  salt,  both  mixed  with  water,  so  as 
to  form  a  thin  paste.  This  quantity  is  sufficient  for  150 
skins  of  ordinary  size ;  wash  them,  and  leave  them  to 
drain,  and  they  are  ready  to  receive  the  oiling.  Fish 
oil  and  tar  from  birch-tree  bark  are  the  substances  used 
for  this  operation,  which  is  practised  in  the  following 
manner : — 

The  leather,  being  damp,  is  placed  wrong  side  upon 
a  table.  The  operator,  having  dipped  his  hand  into  the 
mixture,  passes  it  over  the  skin  by  spreading  it  as 
equally  as  possible. 

The  perfection  of  this  operation  depends  upon  the 
ability  of  the  workmen.  The  proportions  of  oil  and  tar 
vary  according  to  the  size,  nature,  and  quality  of  the 
leather.  Generally  one-third  of  tan  and  two-thirds  of 
oil  are  used.  Sometimes  two-thirds  of  tan  and  a  second 
coating  are  applied  on  the  outside  surface  to  render  it 
less  permeable  to  water.  In  some  shops,  where  they 
desire  to  keep  the  skins  as  white  as  possible,  they  use 
pure  oil,  to  which  is  added  a  little  beef  tallow,  half  a 
pound  being  sufficient  for  an  ordinary  skin. 

This  operation  completed,  the  skins  are  spread  on 
ropes  under  a  well  aerated  shade,  where  they  remain 
until  perfectly  dry.  In  winter  they  are  exposed  to  the 
frost  which  renders  them  white. 

The  Baskirs  and  Kirguises  used  to  prepare  the  skins 
with  smoke,  which  takes  the  place  of  tannin. 


PROCESS  OF  TANNIJNG  SKINS  IN  RUSSIA. 


495 


They  begin  by  strongly  stretching  the  skins  when 
green,  and  taking  off  the  hair  with  a  sickle.  The  skins 
dried  by  the  sun  are  kept  in  till  the  following  spring. 

At  that  time  a  pit  is  dug,  the  size  being  according  to 
the  quantity  of  skins  to  contain;  poles  are  suspended 
on  the  top,  their  ends  reposing  on  the  edges  of  the  pit. 
Then  at  about  five  feet  they  make  a  round  hole  which 
communicates  by  a  little  trench  with  the  bottom  of  the 
pit.  In  this  hole  the  combustible  is  placed;  this  com¬ 
bustible  is  generally  rotten  wood,  as  the  one  giving  the 
most  smoke. 

This  done,  the  fire  is  lit  by  shutting  the  aperture;  the 
smoke  passing  by  the  trench  penetrates  inside  the  pit 
and  spreads  over  the  skins.  After  fifteen  or  twenty-one 
days  of  smoking,  the  skins  are  impregnated  with  the 
volatile  products  of  the  combustion,  and  acquire  some 
of  the  properties  essential  to  the  tanning.  They  are 
more  water  proofs  than  European  leathers.* 

The  currying  is  done  in  Russia  as  anywhere  else,  only 
the  leather  is  streaked  with  a  long  fluted  copper  plate 
about  from  4  to  6  inches  long  and  3  inches  wide,  on 
which  they  bear  the  hand,  which  grains  the  surface. 

The  process  of  preparing  the  tar  is  as  follows;  Take 
large  earthen  pots,  the  bottoms  of  which  are  pierced 
with  a  hole,  which  are  filled  with  birch-tree  bark  well 
packed.  They  are  placed  on  pails  used  as  receivers. 
After  lighting  the  bark,  they  are  covered  with  other 
similar  vessels  pierced  with  a  hole  by  which  the  smoke 
escapes.  The  oil  runs  by  degrees  through  the  aperture 
of  the  lower  vessel  and  falls  into  the  pail  which  sup¬ 
ports  it. 

This  operation  is  done  in  the  spring,  and  they  mix 
with  the  bark  some  branches  covered  with  buds.  That 
mixture  facilitates  the  running  of  the  oil,  which  is  less 
colored  than  by  the  other  process,  the  reason  being  that 
they  dissolve  less  soot.  This  is  why  fresh  bark  is  pre¬ 
ferred  to  that  which  is  dry.  As  Russia  prepares  more 
oil  than  necessary  for  its  consumption,  a  large  quantity 
is  exported. 


*  Bulletin  de  la  Societe  d’encouragement,  vol.  xii.  page  211. 


496 


RUSSIA  LEATHER. 


CHAPTER  CXXXIII. 

RED  LEATHER. 

In  former  times  this  kind  of  leather  was  very  largely 
manufactured,  but  is  replaced  now  by  Morocco  sheep- 
leather;  however,  some  is  still  manufactured,  of  a  finer 
but  of  a  less  permanent  color  than  Russia  leather,  and 
without  its  odor.  These  skins,  used  by  harness,  coach, 
and  trunk-makers,  weigh  on  an  average  from  10  to  1 2  lbs. 

To  prepare  red  leather  choose  fine  clean  skins  with  a 
uniform  smooth  surface.  They  must  not  have  been  tal¬ 
lowed,  but  only  softened  with  a  little  clear  oil,  which  is 
passed  lightly  over  the  surface.  Dip,  pare,  and  wet  them 
in  water,  give  them  a  coating  of  clear  oil  on  the  hair 
side,  and  train-oil  scourging  on  the  flesh  side.  The  pro¬ 
portions  to  use  are  half  a  pound  of  each.  The  skins  are 
then  dried.  Press  on  the  hair  side  with  a  brush,  a  solu¬ 
tion  of  alum  in  water,  which  acts  as  a  mordant  to  fix 
the  color  on  the  skin.  The  skins  are  then  beaten  to 
soften  them,  exposed  to  the  air,  and,  when  dried,  they 
are  rubbed  with  a  cork.  In  that  state  they  are  dried. 
The  color  is  prepared  as  follows: — 

In  a  clean  barrel  put  from  8  to  10  lbs.  of  quicklime, 
with  as  much  water,  and  let  it  stand  for  two  days.  The 
third  day  decant  the  water  without  stirring  the  lime 
deposited  in  the  bottom.  Put  this  water  into  a  copper 
kettle.  To  prepare  two  pailfuls  of  red,  take  8  lbs.  of 
Brazil  wood,  and  boil  strongly  with  the  lime  water ;  as 
the  water  evaporates  add  some  more  so  as  to  have  two 
pailfuls  at  the  end  of  the  ebullition.  Put  this  liquid 
back  on  to  the  fire,  and  boil  it  until  reduced  to  one-half; 
keep  that  solution  in  a  separate  vessel.  Fill  the  kettle 
with  lime  water,  reduce  to  half.  Mix  the  two  liquors 
in  the  kettle,  and  add  to  this  composition  half  an  ounce 
of  powdered  cochineal,  boil  a  few  minutes  and  take  off 
from  the  fire.  While  the  liquid  is  yet  boiling  add  a 
piece  of  lime  the  size  of  an  egg,  and  let  it  cool.  This 
dye  is  sufficient  for  eighteen  to  twenty  skins.  When 
the  dye  is  ready,  give  to  the  skins  a  first  coating,  expose 


SHAGREEN. 


497 


to  the  air,  give  a  second  coating,  and  leave  it  to  dry 
completely.  The  skins  are  then  pounded,  and  they  re¬ 
ceive  a  third  coating  to  which  a  white  of  egg  has  been 
added.  Expose  to  the  air  and  sleek  on  the  hair  side. 
They  are  finally  rubbed  over  in  the  usual  way  with  bar¬ 
berry  juice,  dried,  and  strongly  sleeked. 

Dessables  has  given  another  process  to  dye  the  skins. 
He  makes  a  solution  of  alum  by  dissolving  in  a  kettle  1 
lb.  of  alum  in  1|  pint  of  water.  When  the  solution  is 
made  he  pours  it  into  an  earthen  jar  and  adds  to  it  3  qts. 
of  ordinary  water.  This  solution  is  sufficient  to  mordant 
three  dozen  calf-skins.  Afterwards  take  3  lbs.  of  Brazil 
wood  with  a  piece  of  lime  the  size  of  an  egg.  Boil  the 
whole  in  15  qts.  of  water  for  five  or  six  hours. 

The  skin  being  in  the  same  state  as  for  the  black,  it 
is  well  rubbed  with  a  piece  of  wool  dipped  into  the  alum 
solution,  then  well  dried  and  rubbed  with  the  Brazil. 
Dry  again,  and  rub  with  a  piece  of  wool,  apply  another 
coating  of  Brazil,  dry,  and  repeat  the  operation  a  third 
time. 


CHAPTER  CXXXIV. 

SHAGREEN  AND  PARCHMENT. 

Shagreen. — The  best  quality  of  shagreen  is  manufac¬ 
tured  almost  entirely  in  Astracan  and  other  parts  of 
Asiatic  Russia  ;  gray  and  colored  shagreens  are  imported 
from  Constantinople  and  Tunis  ;  an  inferior  article  is  also 
manufactured  in  Poland.  True  shagreen  is  not  real 
leather,  but  a  skin  prepared  by  drying,  and  without  the 
chemical  action  of  any  tanning  material.  The  following 
process  is  that  which  is  said  to  be  followed  in  Astracan. 
The  raw  materials  employed  are  the  skins  of  horses, 
asses,  camels,  and  only  the  small  strip  from  the  cropper 
along  the  chine  to  the  neck  can  be  employed.  This  is 
cut  off  just  above  the  tail  in  a  semicircular  form,  about 
34  inches  upon  the  cropper  and  28  along  the  back. 
Soak  these  strips  in  water  until  the  hair  is  ready  to  come 
off,  then  separate  it  by  scraping.  Afterwards  dress  the 
32 


498 


RUSSIA  LEATHER. 


pieces  with  the  fleshing  knife  until  all  extraneous  matters 
are  removed,  and  they  have  been  reduced  to  the  thin¬ 
ness  of  a  hog’s  bladder.  Stretch  them  tightly  across 
frames,  and  occasionally  dampen  them  to  prevent  them 
from  shrinking  unequally ;  after  which,  lay  them  on  the 
floor  with  the  flesh  sides  undermost,  and  the  grain  sides 
are  then  thickly  strewed  over  with  the  smooth  hard 
seeds  of  the  alabuta  or  goose  foot  ( chenopodium  album). 
In  some  places,  instead  of  this  mustard  seed  is  used. 
Then  lay  a  felt  over  the  whole,  and  force  the  seeds  deeply 
into  the  soft  moist  skins  by  treading  upon  them  or  by 
the  action  of  a  press. 

This  operation  gives  to  the  hair  side  of  the  shagreen 
its  characteristic  granular  appearance.  Then  dry  slowly 
in  the  shade,  the  frames  with  the  seeds  sticking  in  the 
skins,  until  the  skins  are  ready  to  drop  off  upon  shaking. 
The  skins  are  thus  converted  into  hard  horny  membranes, 
with  the  surfaces  deeply  indented ;  they  are  laid  upon  a 
beam,  padded  with  wool,  are  shaved  down  until  the  de¬ 
pressions  caused  by  the  seeds  become  very  slight  and 
uniform.  First  steep  the  skins  in  water,  and  afterwards 
in  a  warm  alkaline  lye  ;  pile  them  upon  each  other  while 
still  warm’ and  moist.  By  this  means  the  parts  indented 
by  the  pressure  of  the  seeds  regain  their  natural  elasticity, 
and  not  having  lost  substance  by  the  shaving  of  the  rest 
of  the  skins,  they  rise  to  or  above  the  surrounding  level, 
and  form  the  peculiar  grain  of  the  shagreen;  after  this, 
cleanse  the  skins  by  salt  brine  and  dye  them. 

Green  color  is  given  to  shagreen  by  passing  over  the 
flesh  side  a  concentrated  solution  of  sal  ammoniac,  strew¬ 
ing  it  over  with  copper  fillings,  rolling  it  up  with  the 
same  side  inward,  and  pressing  each  skin  for  24  hours 
with  a  heavy  weight.  The  sal  ammoniac  dissolves 
enough  copper  to  give  the  skin  a  beautiful  sea-green 
color. 

Blue  color  is  obtained  with  indigo  dissolved  in  a  solu¬ 
tion  of  soda  with  lime  and  honey.  Black  with  copperas 
and  nutgalls ;  red  with  cochineal.  Pure  white  is  ob¬ 
tained  by  dressing  thq  strips  first  in  an  alum  solution, 


PARCHMENT. 


499 


then  in  wheat  dough,  and  washing  away  the  latter  with 
lime-water. 

The  preparation  is  completed  by  greasing,  carefully 
working  in  hot  water,  currying  with  a  blunt  knife  and 
drying. 

Shagreen  is  rendered  very  hard  by  drying,  but  it 
softens  in  water,  and  in  that  state  will  take  any  shape 
given  to  it,  and  is  used  by  sheath  makers  for  the  cases 
of  spectacles,  surgical  and  mathematical  instruments. 

An  imitation  of  shagreen  has  been  made  so  much  like 
the  genuine  article,  that  it  is  impossible  to  distinguish 
the  difference.  For  this  purpose  sheep  or  goat-skins  are 
used.  Deprive  them  of  hair  in  the  lime  pits,  steep  them 
in  water,  flesh  and  soak  again  ;  rub  them  well  down  upon 
the  horse  with  a  hard  polished  piece  of  wood,  after 
which  they  steep  them  a  third  time,  beat  out  and  trim 
them  on  both  sides.  Then  steep  them  for  two  hours  in 
a  bath  made  of  a  bucket  full  of  tan  for  fifty  skins,  mixed 
with  enough  water  to  cover  the  skins.  An  hour  after 
a  bucket  half  full  of  the  same  is  thrown  in,  and  another 
at  the  end  of  an  hour  and  a  half.  After  this,  keep  them 
in  tan  pits  eight  days,  remove  them,  wring  out,  and  re¬ 
duce  the  thickness  with  the  round  knife  applied  upon 
the  horse.  Dry  them  partially,  stretch  in  the  direction 
of  the  length,  cut  in  half,  blacken  in  the  usual  manner 
and  dry. 

The  grain  is  given  to  this  shagreen  by  means  of  cop¬ 
per  plates  engraved  in  imitation  of  the  roughened  sur¬ 
face  of  the  real  article.  These  plates,  previously  warmed, 
are  placed  upon  the  skins  and  then  subjected  to  the 
action  of  a  press. 


CHAPTER  CXXXY. 

PARCHMENT. 

Parchment  is  the  invention  of  Eumenes,  King  of 
Pergamus,  in  Asiatic  Turkey,  about  200  years  before 
Christ.  It  was  known  in  early  times  as  Pergamena,  and 
was  used,  on  account  of  its  great  durability,  for  records 


500 


CURRYING. 


and  valuable  manuscripts,  and  as  a  substitute  for  the 
papyrus,  or  writing  paper  of  the  ancient  Egyptians. 
The  finest  quality,  made  from  thin  and  perfect  skins, 
and  prepared  by  very  careful  manipulation,  is  called 
vellum. 

Fine  parchment,  for  writings,  is  made  from  the  skins 
of  calves,  kids,  stillborn  lambs,  sheep,  and  she-goats  ;•  but 
an  inferior  quality,  for  drum-heads  and  battledores,  is 
prepared  from  the  skins  of  he-goats,  calves,  wolves,  and 
asses.  Pig-skin  is  also  sometimes  converted  into  parch¬ 
ment  for  bookbinders’  use.  The  operations  are  nearly  the 
same,  throughout,  for  all  the  varieties,  but  are  more 
delicate  for  the  finer  quality. 

The  skins  above  mentioned  are  those  generally  em¬ 
ployed  for  this  branch  of  manufacture,  but  all  other  thin 
skins  are  applicable;  and  sometimes  the  thinner  halves 
of  thick  hides,  split  by  machinery,  are  dressed  by  this 
process. 

“The  skins,  after  having  been  soaked,  limed,  shaved, 
and  Avell  washed,  must  be  set  to  dry  in  such  a  way  as  to 
prevent  their  puckering,  and  to  render  them  easily 
worked.  The  small  manufacturers' make  use  of  hoops 
for  this  purpose,  but  the  greater  employ  a  horse,  or  stout 
wooden  frame.  This  is  formed  of  two  uprights  and  two 
crossbars,  solidly  joined  together  by  tenons  and  mortises, 
so  as  to  form  a  strong  piece  of  carpentry,  which  is  to  be 
fixed  against  a  wall.  These  four  bars  are  perforated 
throughout  with  a  series  of  holes,  which  are  fitted  with 
very  smooth  and  slightly  tapered  box-wood  pins.  Each 
of  these  pins  is  transpierced  with  a  hole  like  a  violin 
screw,  by  means  of  which  the  strings  used  in  stretching 
the  skin  may  be  tightened.  Above  the  horse ,  there  is  a 
shelf  for  such  tools  as  the  workman  may  need  at  hand. 
In  order  to  stretch  the  skin  upon  the  frame,  large  or 
small  skewers  are  employed,  according  to  the  size  of 
the  piece  which  is  to  be  attached  to  it.  Six  holes  are 
made  in  a  straight  line  to  receive  the  larger,  and  four  to 
receive  the  smaller  skewers,  or  pins.  These  small  slits 
are  made  with  a  tool  like  a  carpenter’s  chisel,  and  of  the 
exact  size  to  admit  the  skewers.  The  string  round  the 


PARCHMENT. 


501 


skewer  is  affixed  to  one  of  the  bolts  in  the  frame,  which 
is  turned  round  by  means  of  a  key,  like  that  by  which 
harps  and  pianos  are  tuned.  The  skewer  is  threaded 
through  the  skin  when  in  a  state  of  tension. 

“  Everything  being  thus  prepared,  and  the  skin  being 
well  softened,  the  workman  stretches  it  powerfully,  by 
means  of  the  skewers;  he  attaches  the  cords  to  the 
skewers,  and  fixes  their  ends  to  the  iron  pegs,  or  pins. 
He  then  stretches  the  skin,  first  with  his  hand  applied 
to  the  pins,  and  afterwards  with  the  key.  Great  care 
must  be  taken  that  no  wrinkles  are  formed.  The  skin 
is  usually  stretched  more  in  length  than  in  breadth,  from 
the  custom  of  the  trade;  though  extension  in  breadth 
would  be  preferable,  in  order  to  reduce  the  thickness  of 
the  part  opposite  the  back  bone. 

“The  workman  now  takes  the  fleshing-tool  which  is 
a  semi-circular  doubled-edged  knife,  made  fast  into  a 
double  wooden  handle,  seizes  it  in  his  two  hands  so  as  to 
place  the  edge  perpendicularly  to  the  skin,  and  pressing 
it  carefully  from  above  downwards,  removes  the  fleshy 
excrescences,  and  lays  them  aside  for  making  glue.  He 
now  turns  round  the  horse  upon  the  wall  in  order  to  get 
access  to  the  outside  of  the  skin,  and  to  scrape  it  with 
the  tool  inverted,  so  as  to  run  no  risk  of  cutting  the 
epidermis.  He  thus  removes  any  adhering  filth,  and 
squeezes  out  some  water.  The  skin  must  next  be  ground. 
For  this  purpose,  it  is  sprinkled  upon  the  fleshy  side  with 
sifted  chalk  or  slaked  lime,  and  then  rubbed  in  all  direc¬ 
tions  with  a  piece  of  pumice-stone,  four  or  five  inches 
in  area,  previously  flattened  upon  a  sandstone.  The 
lime  soon  becomes  moist  from  the  water  contained  in  the 
skin.  The  pumice-stone  is  then  rubbed  over  the  other 
side  of  the  skin,  but  without  chalk  or  lime.  This  ope¬ 
ration  is  necessary  only  for  the  best  parchment  or  vellum. 
The  skin  is  now  allowed  to  dry  upon  the  frame,  being 
carefully  protected  from  sunshine  and  from  frost.  In 
the  warm  weather  of  summer,  a  moist  cloth  needs  to  be 
applied  to  it  from  time  to  time,  to  prevent  its  drying  too 
suddenly;  immediately  after  which  the  skewers  require 
to  be  tightened. 


502 


CURRYING.  . 


“  When  it  is  perfectly  dry,  the  white  color  is  to  be  re¬ 
moved  by  rubbing  it  with  the  woolly  side  of  a  lamb-skin. 
But  great  care  must  be  taken  not  to  fray  the  surface;  a 
circumstance  of  which  some  manufacturers  are  so  much 
afraid  as  not  to  use  either  chalk  or  lime  in  the  polishing. 
Should  any  grease  be  detected  upon  it,  it  must  be  re¬ 
moved  by  immersion  in  a  lime-pit  for  ten  days,  and  by 
then  stretching  it  anew  upon  the  horse ,  after  which  it  is 
transferred  to  the  scraper. 

“  This  workman  employs  here  an  edge  tool  of  the 
same  shape  as  the  fleshing-knife,  but  larger  and  sharper. 
He  mounts  the  skin  upon  a  frame  like  the  horse  above 
described  ;  but  he  extends  it  merely  with  cords,  without 
skewers,  or  pins,  and  supports  it  generally  upon  a  piece 
of  raw  calk-skin,  strongly  stretched.  The  tail  of  the  skin 
being  placed  towards  the  bottom  of  the  frame,  the  work¬ 
man  first  pares  off,  with  a  sharp  knife,  any  considerable 
roughness,  and  then  scrapes  the  outside  surface  ob¬ 
liquely  downwards  with  the  proper  tools,  till  it  becomes 
perfectly  smooth.  The  fleshy  side  needs.no  such  opera¬ 
tion,  and,  indeed,  were  both  sides  scraped,  the  skin  would 
be  apt  to  become  too  thin,  the  only  object  of  the  scraper 
being  to  equalize  its  thickness.  Whatever  irregularities 
remain,  may  be  removed  with  a  piece  of  the  finest 
pumice-stone,  well  flattened  previously  upon  a  piece  of 
close-grained  sandstone.  This  process  is  performed  by 
laying  the  rough  parchment  upon  an  oblong  plank  of 
wood,  in  the  form  of  a  stool ;  the  plank  being  covered 
with  a  piece  of  soft  parchment  stuffed  with  wool,  to  form 
an  elastic  cushion  for  the  grinding  operation.  It  is 
merely  the  outside  surface  that  requires  to  be  pumiced. 
The  celebrated  Strasburg  vellum  is  prepared  with  re¬ 
markably  fine  pumice-stones. 

“  If  any  small  holes  happen  to  be  made  in  the  parch¬ 
ment,  they  must  be  neatly  patched,  by  cutting  their 
edges  thin,  and  pasting  on  small  pieces  with  gum-water. 

“  Parchment  is  colored  only  green.  Boil  eight  parts 
of  cream  of  tartar  and  thirty  parts  of  crystallized  verdi¬ 
gris  in  five  hundred  parts  of  rain-water;  and,  when  this 
solution  is  cold,  pour  into  it  four  parts  of  nitric  acid. 


FABRICATION  OF  THE  PATENT  LEATHER. 


503 


Moisten  the  parchment  with  a  brush,  and  then  apply 
the  above  liquid  evenly  over  its  surface.  Lastly,  the 
necessary  lustre  may  be  given  with  white  of  eggs,  or 
mucilage  of  gum  Arabic.” 


SECTION  X. 

PATENT  LEATHER. 

The  fabrication  of  varnished  leather,  or  patent  leather , 
has  reached  such  a  development  in  France  within  the 
last  thirty  years  that  this  kind  is  exported  to  every  coun¬ 
try.  This  fabrication  is  not  difficult,  all  that  it  requires 
is  care  and  dexterity.  There  are  several  processes,  but 
we  think  it  only  necessary  to  describe  in  detail  the  pro¬ 
cess  now  most  usually  followed. 


CHAPTER  CXXXVI. 

FABRICATION  OF  THE  PATENT  LEATHER. 

The  glazing  of  leather  comprises  two  distinct  opera¬ 
tions  : — 

1st.  The  preparation  of  the  surface.  2d.  The  var¬ 
nishing. 

The  object  of  the  preparation  of  the  surface  is  to  close 
the  pores  of  the  leather,  and  make  a  proper  ground  by 
repeatedly  rubbing  the  surface  with  pulverulent  sub¬ 
stances  and  incorporating  them  with  it. 

The  object  of  the  varnishing  is  to  obtain  a  soft,  supple, 
and  bright  coat,  unalterable  by  rubbing. 

To  prepare  the  surface,  incorporate  pulverulent  mat¬ 
ters  which  have  the  property  of  forming  a  mastic  in  the 
pores  of  the  skin,  such  as  chalk ,  ochre ,  lampblack ,  etc. 

In  the  varnish,  on  the  contrary,  no  material  used 
must  destroy  the  transparency  and  brightness. 

The  basis  of  both  preparations  is  siccative  linseed  oil, 
prepared  as  follows : — 


504 


CURRYING. 


For  25  galls,  of  oil,  take — 

20  lbs.  of  lead, 

20  lbs.  of  litharge, 

and  boil  them  together  until  reduced  to  a  syrupy  con¬ 
sistence. 

This  composition  is  then  intimately  mixed  with  ochre 
or  chalk,  according  to  the  fineness  of  the  skin  to  be  pre¬ 
pared,  and  is  uniformly  spread  on  either  sides  of  the 
leather  with  appropriate  tools. 

Three  successive  coatings  are  given  at  such  intervals 
of  time  as  will  permit  each  coating  to  dry,  when  the 
surface  is  rubbed  with  pumice-stone.  A  number  of  thin 
coatings  are  applied  in  the  same  manner,  and  rubbed 
down  until  perfectly  uniform,  and  of  sufficient  thickness 
to  prevent  the  varnish  from  penetrating  the  leather,  by 
which  its  qualities  would  be  injured  and  its  structure 
rendered  hard  and  brittle.  The  oily  substance  of  the 
preparation  and  of  the  varnish  should  merely  penetrate 
deeply  enough  into  the  leather  to  make  the  composition 
of  which  it  is  the  basis  adhere  closely  to  it. 

The  foundation  for  the  varnished  surface  being  thus 
laid,  a  mixture  of  the  above  preparation,  without,  how¬ 
ever,  the  addition  of  ochreous  or  other  earthy  matters ,  and 
well  rubbed  up  with  fine  ivory, black  and  enough  spirits 
of  turpentine  to  make  it  flow  smoothly  and  easily,  is  laid 
on  by  means  of  a  fine  brush,  three  or  four  successive 
coatings  being  applied.  By  this  means  a  black  and 
shining,  pliable  surface  is  obtained,  over  which,  as  soon 
as  it  is  perfectly  dry,  the  varnish  may  be  applied. 

After  the  application  of  each  coating,  the  leather  is 
dried,  by  hanging  it  up,  or  better,  laying  it  out  upon 
frames  or  racks  in  the  drying  room.  Before  varnishing, 
it  is  customary  to  give  a  polish  to  the  surface  by  rubbing 
it  over  with  a  piece  of  woollen  stuff  and  the  finest  kind 
of  pumice-powder  or  tripoli. 

The  varnish  is  thus  prepared :  Take 
Oil  prepared  as  above  20  lbs. 

Asphaltum,  1  lb. 

Thick  copal  varnish,  10  lbs. 

Spirits  of  turpentine,  20  “ 


didier’s  and  other  processes. 


505 


The  asphaltum  and  oil,  being  mixed  together,  are 
heated,  then  the  varnish  and  spirits  of  turpentine  are 
added,  constantly  stirring  until  the  mixture  is  perfectly 
homogeneous.  The  asphaltum  can  be  substituted  by 
Prussian  blue  or  ivory  black.  Leave  the  varnish  to 
settle  in  a  warm  place  for  two  or  three  weeks  before 
using  it. 

During  and  after  the  varnishing,  be  careful  to  avoid 
dust  falling  on  the  prepared  skins. 

The  temperature  of  the  oven  varies  from  133°  to  167° 
according  to  the  nature  of  the  leather  and  varnish. 

The  tint  of  color  of  varnished  leather  varies  with  the 
coloring  material  which  has  been  added  to  the  varnish. 
Asphaltum  gives  it  a  reddish  hue,  Prussian  blue  a  green¬ 
ish-blue  metallic  tint,  and  ivory  black  a  pure  brilliant 
black  lustre. 

Some  manufactures  add  to  the  litharge  employed  for 
boiling  the  oil,  red  lead,  ceruse,  powdered  cuttlefish-bone, 
oxide  of  manganese,  and  various  other  metallic  salts  or 
oxides. 

The  success  of  the  process  depends  very  much  upon 
the  care  with  which  the  skins  prepared  with  it  have 
been  selected,  tanned,  and  curried.  It  is  very  necessary 
that  the  dubbing  should  have  been  applied  to  them  with 
great  uniformity,  and  only  in  small  quantities,  for  other¬ 
wise  the  surface  will  soon  become  tarnished  and  blotted. 


CHAPTER  CXXXVII. 

DIDIER’S  AND  OTHER  PROCESSES. 

Heat  lampblack  in  a  close  vessel,  and  mix  it  with 
linseed  oil  varnish  until  the  mass  becomes  sufficiently 
liquid  to  flow.  Apply  two  coatings  to  the  leather  and 
let  it  dry.  Mix  then  this  varnish  with  an  equal  quan¬ 
tity  of  copal  varnish  and  give  another  coating  to  the 
leather.  As  soon  as  this  last  coating  is  dried,  polish  the 
leather  with  a  felt  charged  with  finely  powdered  pumice 
stone ;  then  pass  on  the  leather  a  waxed  sponge,  wipe 
with  a  cloth,  and  then  give  the  polish.  For  this  purpose 


506 


CURRYING. 


rub  on  a  slab  one  part  of  copal  varnish  with  lampblack, 
and  give  to  the  leather  five  or  six  coatings  of  this  mix¬ 
ture  with  a  brush.  Dry,  rub  the  leather  with  pumice 
stone,  and  give  again  two  coatings  of  copal  varnish. 

White  polished  leather. — Rub  ceruse  with  white  oil 
varnish,  and  apply  two  coatings  on  the  leather.  Then 
rub  Krem’s  white  at  first  with  water,  let  it  dry  and  rub 
it  with  white  copal  varnish,  give  three  or  four  coatings, 
and  polish  as  above. 

Red  polished  leather. — The  first  coating  is  given  with 
shellac  mixed  with  spirit  of  turpentine  and  the  second 
with  the  same  lac  in  copal  varnish.  This  latter  is  pre¬ 
pared  by  dissolving  one  part  of  copal  in  two  parts  of 
turpentine  and  adding  to  this  solution  an  equal  quantity 
of  linseed  oil  varnish. 

Blue  polished  leather. — Give  a  first  white  coating  with 
ceruse  mixed  with  oil  varnish,  then  a  blue  coating  with 
Prussian  blue  mixed  with  copal  varnish. 

Yellow  polished  leather. — Yellow  requires  a  white 
leather  prepared  by  boiling  it  in  a  copper  vessel  con¬ 
taining  a  solution  composed  of  fustic  wood,  lye,  cochi¬ 
neal  and  alum ;  pass  this  liquid  through  a  cloth,  give  a 
coating  to  the  leather,  and  when  dried,  apply  the  copal 
varnish.  If  no  white  leather  is  at  hand,  give  a  first  bot¬ 
tom  with  light  yellow  ochre  and  ceruse  mixed  with  ordi¬ 
nary  varnish.  The  second  coating  is  given  with  the 
same  color  mixed  with  copal  varnish.  When  dry,  polish 
the  surface,  and  apply  three  coatings  of  yellow  cassel 
mixed  with  copal  varnish. 

Polished  leather  of  leather  color. — Apply  a  coating  of  a 
mixture  of  yellow  ochre,  white  lead,  and  oil  varnish ; 
when  dry,  polish.  Give  a  second  coating  with  Turner’s 
yellow  mixed  with  copal  varnish. 

Black  Lacquer  for  Shoes  and  Leather  Work. — Mix  four 
ounces  of  shellac  and  half  an  ounce  of  finest  lampblack 
in  a  stone  bottle  with  lj  pint  of  strong  alcohol,  close 
the  mouth  of  the  bottle  with  a  damp  bladder.  Add 
nothing  more  to  the  mixture  for  twenty-four  hours,  but 
shake  it  often  in  that  time.  Then  pierce  a  hole  in  the 
bladder  with  a  needle,  and  place  the  bottle  in  hot  water, 


WATER-PROOF  LEATHER. 


507 


and  let  it  stand  half  an  hour,  taking  it  out  often  to  shake 
it.  Unfasten  the  bladder,  pour  an  ounce  of  Venetian 
turpentine  in  the  bottle,  close  up  the  mouth  again,  and 
place  it  once  more  in  hot  water.  The  bottle  should  be 
kept  always  corked,  and  it  requires  to  be  shaken  before 
using  the  contents. 

Process  for  Varnishing  Leather  for  Belts ,  etc. — The 
varnish  for  leather  is  the  same  as  for  carriages,  except 
that  it  contains  less  copal,  and  that  the  oil  used  in  the 
varnish  for  certain  coarse  articles  should  be  a  little  de¬ 
composed. 

After  having  dressed  and  scraped  the  leather  to  be 
varnished,  apply  upon  the  flesh  side  a  thin  coat  of  glue 
water,  to  which  has  been  added  about  one  ounce  of 
boiled  linseed  oil.  The  leather  when  dried  is  polished, 
and  successive  coatings  applied  until  it  becomes  very 
smooth.  Then  mix  one  part  of  strong  drying  oil,  and  one 
part  of  copal  varnish  in  an  iron  vessel,  add  well  pulverized 
lampblack  and  spirits  of  turpentine,  and  set  the  whole 
over  a  fire.  The  leather  which  during  this  time  has 
been  kept  in  a  closet  artificially  heated,  is  now  stretched 
upon  a  table,  a  very  thick  coat  of  the  mixture  quickly 
laid  on  with  a  flat  brush,  immediately  placed  in  a  warm 
closet  and  allowed  to  dry  slowly.  When  dried  it  is 
polished  with  pumice  stone,  or,  which  is  better,  with 
charcoal  finely  powdered  and  sifted.  A  second  coat  is 
applied  in  the  same  way,  and  the  operation  finished 
with  a  third  coat,  which  should  be  very  lightly  laid  on 
and  be  very  smooth.  The  leather  is  now  dried  without 
polishing. 


SECTION  XI. 

WATER-PROOF  LEATHER. 

Many  processes  have  been  proposed  to  render  leather 
water  proof.  Those  processes  which  rest  upon  the  in¬ 
crease  of  the  density  of  the  matter  by  the  use  of  fat, 


508 


CURRYING. 


resinous  or  gummy  matters  present  no  great  interest; 
nevertheless,  for  the  satisfaction  of  the  reader,  we  shall 
give  a  few  of  them. 


CHAPTER  CXXXVIII. 

PROCESS  OF  J.  SMITH  AND  J.  THOMAS. 

Macerate  the  leather  you  want  to  render  water  proof 
in  water  for  twenty-four  hours ;  then  press  it  between 
two  iron  cylinders,  and  let  it  dry  in  the  air  for  five  days. 
Then  mix  the  following  liquors  : — 


Linseed  oil  .  .  .  .4  pints 

Olive  oil  .  .  .  .  2  “ 

Spirit  of  turpentine  .  .  I  “ 

Castor  oil  .  .  .  2  “ 

Beeswax  .  ...  8  ounces 

Pitch  .  .  .  .  4  “ 


Boil  all  these  substances  over  a  gentle  fire  in  an  earthen 
vessel,  and  during  the  ebullition  dip  in  the  leathers 
which  leave  more  or  less  time,  according  to  their  nature. 

Sole  leather  must  stay  about  twenty  minutes.  Calf 
and  cow-skins  about  ten  minutes.  Those  leathers  thus 
prepared  are  drained  and  pressed  between  two  iron  cyl¬ 
inders  covered  with  leather.  Dry  them  with  an  oven 
heated  at  77  to  86°,  press  them  again  and  put  them 
anew  in  the  oven. 


CHAPTER  CXXXIX. 

NENORY’S  PREPARATION  TO  RENDER  LEATHER  WATER 
PROOF  AND  IMPERVIOUS. 

The  preparation  of  this  compound  is  made  as  fol¬ 
lows  : — 

Preparation  of  Siccative  Oil. — Take  100  lbs.  of  lin¬ 
seed  oil  and  13  lbs.  of  litharge;  boil  them  together  at 
a  moderate  heat  for  several  hours,  until  the  oil  is  re¬ 
duced  to  two-thirds. 


PROCESS  FOR  RENDERING  LEATHER  IMPERVIOUS.  509 


Preparation  of  the  Plastic  Gum. — Take — 


Old  linseed  oil 

.  lbs. 

White  wax  . 

.  1  lb. 

Glue 

.  5^  lbs. 

Verdigris 

.  .  4  oz. 

Water 

.  2  qts. 

Melt  the  whole  at  a  gentle  heat,  in  an  iron  vessel, 
until  it  forms  a  homogeneous  mass. 

Preparation  of  the  Compound. — Take — 


Siccative  oil  prepared  as  above  .  .100  lbs. 

Gum  prepared  as  above  ...  3  “ 

Beeswax  .  .  .  .  .  .  10  “ 

Spirit  of  turpentine  .  .  .  .  13  “ 

Balsam  of  Peru  .....  2  “ 

Oil  of  thyme  .  .  .  .  .  .  .  2  “ 

White  pitch  ......  6  “ 


Melt  the  whole  in  an  iron  vessel  at  a  gentle  heat 
without  boiling ;  then  pour  this  composition  in  the  bot¬ 
tles  which  must  keep  it. 

Process  of  Using  the  Composition. — Put  the  bottle 
near  the  fire,  so  as  to  render  it  fluid  without  heating  it. 
After  having  well  dried  and  brushed  the  leather,  pass 
the  composition  over  it  with  a  little  sponge  or  a  brush, 
and  during  the  operation  expose  the  leather  to  the  sun 
or  to  a  gentle  heat.  When  the  leather  is  dried,  repeat 
the  operation  until  saturated.  If  it  stays  on  the  leather, 
some  composition  which  has  coagulated,  rub  it  with  a 
rough  cloth,  then  apply  any  kind  of  blacking. 


CHAPTER  CXL. 

DEANE’S  PROCESS  FOR  RENDERING  LEATHER 
IMPERVIOUS. 

For  Composition. — 1.  Take:  Linseed  oil,  rape-seed 
oil,  neats-foot  oil,  251  gallons  ;  boil  until  reduced  to 
21  \  gallons. 

2.  Take:  Mutton  or  tallow  suet;  melt  it  at  a  gentle 
heat ;  pass  it  through  a  sieve  ;  boil  it  one  hour  in  water, 
filter  and  let  it  cool,  and  put  the  cakes  on  cotton  cloth 
to  absorb  the  dampness. 


510 


CURRYING. 


3.  Take  of  the  grease  prepared  above  (2)  34|  lbs.  and 
34J  lbs.  of  fresh  wax ;  melt  them  together,  and  keep 
them  at  a  temperature  of  158°,  until  the  whole  is  well 
incorporated. 

4.  Take  2  lbs.  and  2  drs.  of  India-rubber  in  shreds, 
that  you  dissolve  in  8  quarts  of  rectified  spirits  of  tur¬ 
pentine  at  a  temperature  of  248°,  over  a  sand-bath. 

5.  Take  10  lbs.  and  1  drachm  of  Burgundy  pitch, 
that  you  melt  with  2|  gallons  of  spirits  of  turpentine  at 
194°,  over  a  water-bath  ;  leave  this  mixture  to  cool  until 
it  reaches  158°,  then  add  it  to  the  above  mixture,  and 
stir  the  whole  until  well  incorporated. 

Second  Composition. — 1.  Take  oil,  grease,  and  melted 
wax ;  mix  as  above  at  a  temperature  of  158°. 

2.  Take  4  gallons  of  turpentine,  in  which  you  dis¬ 
solve  10  lbs.  1  drachm  of  yellow  rosin  over  a  sand-bath, 
at  a  temperature  of  200°. 

When  the  mixture  thus  prepared  has  cooled  to  158°, 
add  the  resinous  composition  to  that  of  oil,  grease,  and 
wax ;  stir  the  whole  until  cold. 

Third  Composition. — Take  2\\  gallons  of  pure  whale 
oil,  and  from  13  to  17  lbs.  of  India-rubber  shreds;  heat 
them  together  at  194°  to  240°,  which  is  sufficient  to 
operate  the  dissolution  of  the  India-rubber. 

Fourth  Composition. — Take  rectified  spirits  of  turpen¬ 
tine,  sufficient  to  cover  13  or  17  lbs.  of  India-rubber 
shreds ;  boil  gently  over  a  second-bath  heated  at  240°, 
until  the  entire  dissolution  of  the  India-rubber;  add  to 
this  composition  21  gallons  of  pure  whale  oil  at  194°, 
and  keep  thus  until  the  mass  is  fluid  and  united ;  let 
the  temperature  fall  to  158°;  add  8|  lbs.  of  fresh  wax; 
stir  the  whole  until  cold. 

Application  of  the  Composition. — The  first  and  second 
compositions  are  used  for  skins,  and  the  third  and  fourth 
for  leathers. 

The  skins  are  saturated  with  the  first  or  second  com¬ 
position,  by  spreading  them  in  a  vessel  which  communi¬ 
cates  with  a  kettle  in  which  is  the  composition.  Intro¬ 
duce  the  composition  heated  from  144°  to  212°  in  the 
vessel  containing  the  skins  until  entirely  covered ;  leave 


DIFFERENT  PROCESSES. 


511 


them  thus  two  or  three  hours.  The  skins  are  then 
withdrawn,  and  submitted  to  a  current  of  air  gently 
heated,  until  dry.  In  this  process  hydrostatic  pressure 
or  vacuum  can  be  used  the  same  as  we  have  seen  for 
tanning. 

The  leathers,  if  thin,  are  impregnated  with  the  third 
composition  ;  if  thick,  with  the  fourth.  They  are  placed 
on  a  metallic  plate,  heated  at  104°,  and  they  are  covered 
with  the  composition  by  using  a  brush.  The  saturation 
is  achieved  by  rarefying  the  air  contained  in  a  room 
purposely  constructed. 

You  operate  on  leather  by  exposing  it  in  a  room  at  a 
temperature  of  100  to  120°  ;  then  one  or  two  hours 
after,  when  warm,  coat  them  with  one  of  the  above 
compositions  until  well  saturated  ;  place  them  in  a  room 
at  the  ordinary  temperature,  and  leave  them  in  until 
dry. 


CHAPTER  C  X  L  I .  ' 

DIFFERENT  PROCESSES. 

Cheap  Method  of  Making  Leather  Water-proof— 
Melt  together  in  an  earthen  pipkin 

Tallow . 2  lbs. 

Lard  .  .  .  .  .  .  1  lb. 

Turpentine  .  .  .  .  j  “ 

Beeswax  .  .  .  .  .  “ 

Dry  the  leather  well  and  warm  it.  Rub  the  composi¬ 
tion  into  them  with  a  piece  of  tow  dipped  into  it,  the 
articles  being  held  near  a  hot  fire  until  they  have  had 
rubbed  on  them  as  much  as  they  can  take  up. 

There  is  another  mixture  much  used  by  fishermen, 
which  consists  in  melting  together 

Beeswax  .  .  .  .  .  1  lb. 

Rosin . \  “ 

Suet  . . \  “ 

Jennings'  Process. — Dissolve  any  metallic  soap  in  an 
equal  quantity  of  raw  linseed  oil,  and  immerse  the 


512 


CURRYING. 


leather  in  that  solution  heated  at  225°.  When  the  lat¬ 
ter  has  become  cold,  take  the  leather  out  and  dry  it  in 
the  air.  Forty-eight  hours  are  sufficient  for  the  whole 
process. 

Canvas  and  similar  fabrics  can  also  be  rendered  water¬ 
proof  by  the  following  process: — 

Dissolve 

Soft  soap  .  .  .  .  100  lbs. 

In  boiling  water  ...  30  galls. 

Heat  the  solution  to  212°  with  66  lbs.  of  sulphate  of  zinc. 
An  insoluble  salt  of  zinc  is  formed,  while  the  sulphate 
of  potash  dissolves  in  water ;  the  metallic  soap  rises  on 
the  surface  of  the  liquor,  and  is  boiled  in  fresh  water  to 
purify  it. 

Boil  5  lbs.  of  pearlash  with  50  galls,  of  raw  linseed 
oil,  until  the  mixture  assumes  a  soapy  appearance,  and 
to  it  while  hot  add,  stirring  all  the  time, 

Sugar  of  lead  ...  2^  lbs. 

Litharge  ....  2  “ 

Red  lead  ....  4  “ 

Black  rosin  .  .  .  21  “ 

Boil  one  hour,  constantly  stirring,  and  at  the  end  of  that 
time  add  30  lbs.  of  the  metallic  soap. 

Add  to  the  mixture  two  gallons  of  a  liquor  made  by 
dissolving  India-rubber,  24  ounces  in  one  gallon  spirit 
of  turpentine.  Allow  the  mixture  to  cool  to  160°,  and 
apply  it  with  a  brush.  Two  or  three  coatings  are  suffi¬ 
cient,  but  there  must  be  an  interval  between  each  coat¬ 
ing  to  insure  a  perfect  drying. 


PART  IY. 


HUNGARY  LEATHER. 


SECTION  XII. 

This  method  of  preparing  skins,  analogous  to  tanning, 
was  originally  introduced  into  Hungary  from  Senegal. 
It  was  imported  into  France  in  1573,  by  a  tanner  of 
the  name  of  Boucher.  In  the  next  century  the  great 
Colbert  established  a  manufactory  at  St.  Cloud,  in  which 
the  process  was  adopted;  and,  in  1702,  this  establish¬ 
ment  was  removed  to  La  Roquette,  in  Paris,  in  which 
it  was  in  successful  operation  for  a  long  time. 

The  process  of  manufacturing  Hungary  leather  is  a 
rapid  one;  it  consists  in  impregnating  strong  hides  with 
alum,  common  salt,  and  suet;  and  is  almost  the  same 
as  when  first  introduced  from  Hungary.  The  only  im¬ 
provement  we  know  is  the  one  introduced  by  Curan- 
deau,  of  which  we  shall  speak  hereafter.  This  kind  of 
leather  is  manufactured  all  the  year  round,  measures 
being  adopted  to  counteract  any  injurious  influences  the 
temperature  might  exert  upon  it. 

The  workshop  is  divided  into  two  parts:— 

1st.  A  shed  on  the  bank  of  a  river  in  which  are 
placed  the  beams,  the  fleshing  and  paring-knives,  and 
the  scraping-stones.  In  a  corner  is  a  furnace  to  prepare 
the  solution  of  alum,  and  near  it  are  two  tubs  to  im¬ 
merse  the  skins.  Besides  this  a  number  of  ordinary 
tubs  is  required. 

2d.  The  other  part  of  the  factory  consists  of  a  room 
6  feet  high  by  15  feet  square,  perfectly  tight,  so  as  to 
retain  the  heated  air.  In  a  corner  of  this  room  is  a  fur¬ 
nace,  fed  with  fuel  through  a  door  opening  externally, 
upon  which  is  placed  a  copper  kettle,  capable  of  con- 
33 


514 


HUNGARY  LEATHER. 


taming  160  lbs.  of  tallow.  In  the  middle  of  this  kind 
of  oven  is  a  square  stove,  upon  which  an  iron  grating, 
three  feet  square,  is  placed  for  the  reception  of  coals. 
On  either  side  of  this  oven,  and  occupying  its  whole 
length,  are  large  tables  upon  which  the  skins  are  greased. 
The  upper  part  below  the  ceiling  is  filled  with  poles, 
upon  which  the  leather  is  hung  in  order  to  dry.  The 
door  of  this  room  fits  closely  to  its  joints,  so  as  to  pre¬ 
vent  the  entrance  of  cold  air. 

The  most  suitable  hides  for  Hungary  leather  are 
strong  ox-hides,  but  bull  and  cow-skins  can  be  prepared 
in  the  same  manner.  The  process  is  rapid,  and  may  be 
completed  in  two  months  or  less  time.  These  hides  can 
scarcely  be  compared  with  those  tanned  and  curried  in 
the  ordinary  way,  since  they  consist  of  the  original  tis¬ 
sue  of  the  skins  condensed  and  slightly  altered  in  cha¬ 
racter  by  the  process  to  wdiich  they  are  subjected,  but 
not  converted  into  true  leather  by  combination  with 
tannin.  Moreover,  they  are  employed  for  different  pur¬ 
poses. 

The  chief  operations  to  which  hides  are  subjected  are 
the  following: — 


1.  The  river-work, 

2.  Aluming, 

3.  Second  aluming, 

4.  Drying, 

5.  Stretching, 


6.  Treading  out, 

7.  Tallowing, 

8.  Flaming, 

9.  Airing, 

10.  Marking  and  piling. 


Before  describing  these  operations  we  shall  say  a  few 
words  on  the  different  greases  employed  in  this  process. 


CHAPTER  CXLII. 

GREASE  AND  ANIMAL  OILS. 

These  substances  of  animal  origin  are  wThite  or  yel¬ 
lowish,  sometimes  odorless,  sometimes  with  a  strong 
odor.  The  consistence  is  variable ;  the  taste  is  sweet, 
lighter  than  water,  without  action  on  litmus,  more  or 
less  fusible,  alterable  in  the  air,  insoluble  in  water,  solu¬ 
ble  in  alcohol  which  dissolves  the  oleine. 


GREASE  AND  ANIMAL  OILS. 


515 


Greases  are  composed  of  two  principles,  one  liquid, 
the  oleine,  the  other  solid  stearine  and  margarine ;  and 
it  is  according  to  the  proportions  of  the  latter  that  de¬ 
pend  the  fusibility  of  the  grease. 

Lard  is  white,  inodorous,  soft ;  melts  at  80.6°,  is  in¬ 
soluble  in  water;  100  parts  of  boiling  alcohol  dissolve 
2.80  which  are  oleine.  Treated  by  caustic  alkalies,  it 
is  converted  into  glycerine  and  oleate,  margarate,  and 
stearate,  of  these  bases,  which  by  their  union  constitute 
the  soaps. 

According  to  M.  Chevreul,  lard  is  composed  of  oleine 
and  stearine,  and  its  elementary  constituents  are  repre¬ 
sented  as  follows : — 

Chevreul.  Saussure. 

.  79.098  78.843 

.  11.146  12.182 

.  9.756  8.502 

0.473 

100.000  100.000 

This  substance  is  employed  in  currying,  Hungarying, 
etc. 

Mutton  Suet. — This  grease  is  firmer  than  the  above, 
odorless,  insipid ;  brittle  when  pure ;  insoluble  in  water, 
and  very  moderately  so  in  alcohol.  100  parts  of  alcohol 
dissolve  only  2.26  of  oleine. 

According  to  Mr.  Chevreul  it  is  composed  of  oleine, 
stearine,  and  a  small  quantity  of  hircine.  Its  element¬ 
ary  principles  are  as  follows  : — 

Carbon  ....  78.996 

Hydrogen  .  .  .  .  11.700 

Oxygen  ....  9.304 

100.000 

Beef  Tallow. — This  tallow  has  a  light  yellowish  color. 
It  is  firm,  brittle,  fusible  at  104°,  insoluble  in  water, 
soluble  in  boiling  alcohol.  Its  properties  and  composi¬ 
tion  are  the  same  as  the  above. 

Medullary  Beef  Tallow. — This  kind  of  grease  is  of  a 
bluish-white  color,  fusible  at  113°.  It  is  composed  of 


Carbon  . 
Hydrogen 
Oxygen  . 
Nitrogen 


516 


HUNGARY  LEATHER. 


Solid  grease 
Oil  . 


76 

24 


100 


The  oil  has  a  very  disagreeable  odor,  and  is  nearly 
colorless. 

Fish  Oils. — From  fish  a  kind  of  greasy  fluid  is  obtained 
which  we  call  oil,  giving  to  it  the  name  of  the  fish  it  is 
extracted  from.  While  spermaceti  is  not,  properly  speak¬ 
ing,  an  oil,  however,  as  it  has  some  of  its  characters,  it 
may  be  included  among  them. 

Dolphin  Oil. — This  oil  is  extracted  from  the  dolphin, 
Delphinus  glohiceps.  Its  color  is  lemonish.  Its  odor 
similar  to  that  of  the  fish.  Its  specific  gravity  is  0.9178. 
100  parts  are  dissolved  in  100  parts  of  alcohol  at  0.812, 
at  a  temperature  of  158°.  Its  solution  has  no  action  on 
litmus.  This  oil  exposed  to  a  cold  of  26.6°  separates 
into  a  crystalline  substance  and  an  oil  which  solidify  at 
28.4°.  The  crystalline  matter  is  much  similar  to  cetine. 
It  is  formed  of  oleine,  phocenin,  and  a  little  phocenic 
acid. 

Porpoise  Oil  is  extracted  as  the  above,  from  the  Del¬ 
phinus  phoccena.  It  is  yellowish.  Its  specific  gravity  is 
0.937 ;  without  action  on  litmus,  soluble  in  alcohol,  and 
saponifiable  in  alkalies.  It  is  composed  of  oleine,  phoce- 
nine,  an  orange-red  principle,  an  odoriferous  principle, 
and  phocenic  acid. 

Different  Fish- Oils. — This  oil  belongs  to  different 
fishes,  particularly  to  the  whale.  The  oil  is  separated 
by  pressure  from  the  solid  grease.  It  is  fluid,  sometimes 
colorless,  sometimes  of  a  reddish-brown  with  a  disagree¬ 
able  odor.  According  to  Mr.  Chevreul,  it  is  formed  of 
oleine,  stearine,  two  odoriferous  and  coloring  principles. 
It  possesses  a  great  similarity  to  fixed  oils.  Its  elemen¬ 
tary  principles,  according  to  Berard,  are — 


Carbon 
Hydrogen  . 
Oxygen 


79.65 

14.35 

6.00 


100.00 


RIVER  WORK. 


517 


Process  by  which  to  give  to  a  mixture  of  different  Oils 
and  Greases  the  properties  of  Fish  Oils. — Take  the  in¬ 
ferior  qualities  of  seed-oils  and  boil  them  several  times 
in  a  kettle  to  separate  the  aqueous,  earthy,  and  acid  parts. 
Boil  putrefied  horse  guts  or  bad  fishes.  Mix  these  two 
substances  in  the  kettle.  Add  seed-oils,  horse-fat,  re¬ 
siduum  of  seed-oils  purified  by  sulphuric  acid,  and  at 
last  whale  or  cod-liver  oil.  Stir  this  mixture  for  twenty- 
four  hours  in  the  kettle.  Leave  to  settle ;  pass  through 
a  skimmer.  You  obtain  thus  an  oil  as  good  as  cod-liver 
oil,  which  is  the  best. 

Process  of  rendering  Vegetable  Oils  fit  to  take  the  place 
of  Fish  Oils. — Melt  in  a  kettle  over  a  gentle  fire  16  lbs. 
of  lard,  mixed  with  100  lbs.  of  nut  oil  or  linseed  oil,  or 
any  other  seed  oils.  Stir  well,  till  the  mass  is  homoge¬ 
neous.  Take  off  of  the  fire,  and  when  partially  cold, 
pour  in  it  while  stirring  four  ounces  of  sulphuric  acid. 

This  oil  has  the  same  properties  as  fish  oils. 

CHAPTER  CXLIII. 

RIVER  WORK. 

The  first  operations  are  similar  to  those  of  tanning 
and  tawing.  The  hides  are  washed,  cut  in  two,  scraped 
upon  the  horse  with  a  round  knife,  and  are  then  care- 


Fig.  150. 


fully  and  slightly  washed ;  the  fat  and  flesh  alone  being 
removed. 


518 


HUNGARY  LEATHER. 


Afterwards  scrape  off  the  hair  from  the  hides,  by  plac¬ 
ing  them  upon  a  bed  of  other  skins  folded  double  and  so 
disposed  upon  the  horse  as  to  present  a  smooth  and  per¬ 
fectly  uniform  surface.  This  operation  must  be  care¬ 
fully  conducted  to  avoid  injuring  the  surfaces,  and  it  will 
take  one  day  for  a  skilful  workman  to  separate  the  hair 
from  eight  or  ten  hides.  Then  soak  the  skins  in  the 
river  for  twenty-four  hours,  or  in  vats  for  three  days, 
changing  the  water  twice  a  day  in  summer  and  once  in 
winter.  If  you  soak  in  running  water,  drive  a  stake 
into  the  ground,  and  fasten  the  hides  to  it  by  a  cord 
passing  through  the  hide  holes,  or  those  left  by  the  re¬ 
moval  of  the  horns. 


CHAPTER  CXLIY. 

ALUMING  THE  HIDES. 

The  aluming  is  the  most  important  preparation  to 
which  Hungary  leather  is  submitted.  Not  only  does  it 
prevent  a  putrefaction  of  the  hides,  but  effects  a  chemi¬ 
cal  change  in  them,  by  which  they  are  rendered  stronger 
and  more  substantial.  The  exact  nature  of  this  chemical 
influence  is  not  known  yet,  but  the  supposed  reaction  is 
as  explained  under  kid-leather. 

The  hides  are  first  treated  with  a  mixture  of  alum 
and  salt,  by  which  a  portion  of  the  sulphate  of  alumina 
is  transformed  into  chloride  of  aluminium.  This  salt 


Fig.  151. 


softens  the  effects  of  the  alum,  attracts  moisture  of  the 
atmosphere,  and  preserves  the  suppleness  of  the  leather. 


ALUMXNG  THE  HIDES. 


519 


Generally,  the  manufacturer  works  nine  hides  at  a  time. 
When  the  skins  are  ready  to  be  alumed,  dissolve  alum 
and  salt  in  a  kettle  disposed  on  a  furnace.  This  kettle 
is  round  below,  and  of  a  size  according  to  the  quantity 
of  skins  to  be  treated.  An  ordinary  kettle  is  14  inches 
deep  in  the  middle  and  about  22  inches  diameter,  and  is 
large  enough  to  alum  nine  skins  at  a  time. 

The  proportions  of  alum  and  salt  used  are  for  each  skin— 

Alum  .....  6  lbs. 

Salt . “ 

Water  .  .  .  .  .  7^  galls. 

Heat  the  water  at  about  122°,  throw  in  it  the  alum  and 
salt,  and  stir  until  dissolved. 

When  the  solution  is  ready,  put  the  skins  in  two 
vats,  4  feet  10  inches  long,  3  feet  wide,  and  27  inches 
deep. 

When  nine  hides  or  eighteen  strips  are  worked  to¬ 
gether,  the  whole  is  divided  into  three  lots  of  three  skins 
each.  Three  strips  are  placed  in  each  vat,  being  prepared 
upon  each  other  with  the  hair  side  up,  and  so  arranged 
that  the  head  of  the  second  one  is  above  the  tail  of  the 
first,  and  so  on.  It  may  occur  that  the  leathers  are  very 
strong  and  large,  and  require  much  care,  then  instead  of 
three  lots  you  make  four. 

When  the  leathers  are  thus  disposed  you  alum  them. 
For  this  purpose  take  in  the  kettle  two  or  three  pailfuls 


Fig.  152. 


of  the  alum  solution.  This  solution  must  be  tepid,  for  if 
too  warm  it  will  burn  the  leather.  Heat  gradually,  so 


520 


HUNGARY  LEATHER. 


that  the  last  is  warmer  than  the  one  before  used.  Pour 
this  water  on  the  hides.  Then  a  man  beats  them  with 
his  feet.  This  operation  is  renewed  three  times.  Each 
time  the  workman  beats  with  the  feet,  twice  the  backs 
and  once  the  bellies.  Each  three  turns  forms  what  is 
called  one  water.  During  this  operation  another  man 
puts  tepid  water  in  the  second  »vat,  and  disposes  the 
strips  as  above  indicated. 

This  first  water  done,  the  man  passes  in  the  second 
vat  and  begins  the  same  operation.  For  each  three  skins 
you  give  four  waters  in  the  same  manner,  but  each  time 
the  liquor  must  be  warmer. 

After  the  fourth  water  fold  the  hides  double  and  de¬ 
posit  them  in  tubs  2  feet  diameter  and  2  feet 
Fig.  153.  deep.  Fill  this  tub  with  alum  water  which 
has  been  used,  and  immerse  the  hides.  Gene¬ 
rally,  the  hides  are  left  in  these  tubs  eight 
days,  the  position  being  changed  every  day 
or  two.  Some  manufacturers  leave  them  a 
longer  time  in  winter,  but  no  difference  need  be  made  in 
this  respect  between  the  seasons. 


CHAPTER  CXLY. 

SECOND  ALUMING. 

The  skins  being  removed  from  the  tubs  and  well 
shaken  to  remove  the  folds,  they  are  subjected  to  the 
same  series  of  operations  as  in  the  first  aluming.  Steep 
them  twenty-four  hours  in  the  same  alum  water,  take 
them  out,  and  leave  them  to  drain  on  planks  arranged 
in  a  slanting  position,  so  that  the  liquor  escaping  from 
the  hides  runs  back  into  the  vats. 


CHAPTER  CXL  YI. 

DRYING  AND  STRETCHING. 

When  the  hides  are  perfectly  drained,  make  four  holes 
in  each  strip,  and  thrust  a  stick  through  them ;  the  stick 


TREADING  OUT  THE  HIDES. 


521 


is  supported  by  its  two  ends  upon  poles  near  the  ceiling 
of  the  drying  room.  Suspend  the  hides  and  leave  them 
till  nearly  dried.  Take  them  down,  lay  them  upon  the 
floor,  being  folded  double  with  the  hair  sides  within ;  a 
workman  stretches  all  their  parts  and  takes  out  the 
wrinkles,  which  have  formed  in  them  by  forcibly  drawing 
a  stick  2  ft.  long  and  about  f  of  an  inch  in  diameter,  in 
every  direction  over  the  surfaces.  Then  pile  up  the 
hides,  leave  them  a  day  or  two  in  this  state,  suspend 
them  upon  the  poles  until  thoroughly  dried. 

During  cold  weather  hang  the  hides  for  a  time  on  the 
poles  in  the  store-room,  heated  with  charcoal.  When 
sufficiently  warm  stretch  and  pile  them  one  upon  the 
other,  and  cover  them  with  cloths  to  protect  them  from 
the  cold.  Thus  prepared,  this  leather  keeps  as  well  as 
tanned  leather,  and  it  is  only  necessary  to  have  dry 
winds,  to  avoid  exposure  to  a  hot  sun,  in  order  that  it 
may  not  become  so  dry  as  to  be  worked  afterwards  with 
difficulty. 


CHAPTER  CXLYII. 

TREADING  OUT  THE  HIDES. 

The  leather  being  dried,  is  softened  and  prepared  to 
receive  the  tallow,  by  a  peculiar  method  of  stamping. 
Erect  a  platform  with  planks  slanting  in  one  direction, 


Fig.  154. 


522 


HUNGARY  LEATHER. 


and  supported  upon  cross  pieces  12  to  13  inches  apart. 

The  hide  to  be  worked  is  folded,  double, 
Fig.  155.  with  the  hair  side  in  contact,  and  a 
'  smooth  stick  of  hard  wood,  26  inches 

long  and  three-quarters  of  an  inch  in 
diameter,  is  passed  through. 

The  workman  wears  thick-soled  shoes  without  heels, 
and  stands  upon  the  folded  strip,  laid  upon  the  upper 
part  of  the  platform;  and,  holding  on  to  a  railing,  he 
proceeds  to  roll  the  stick  by  repeated  stamping  and 
shuffling  movements  of  his  feet  from  its  first  position  to 
the  edge  of  the  strip.  He  repeats  again  and  again, 
changing  the  position  of  the  stick,  and  the  hide  is 
turned  until  every  part  is  well  tramped.  He  folds  the 
leather  in  the  opposite  direction,  so  that  the  flesh  side  is 
in  contact,  and  it  is  exposed  again  to  the  stamping  pro¬ 
cess.  He  continues  the  operations  until  the  pores  be¬ 
come  as  soft  and  supple  as  it  is  possible  to  make  them. 
Then  he  piles  the  strips  upon  each  other  for  a  time,  and 
if  not  sufficiently  dry,  he  exposes  them  to  a  hot  sun  or  to 
the  heat  of  the  drying  room ;  then  he  treads  them  out  a 
second  time  precisely  in  the  same  manner  as  before. 


CHAPTER  CXLVIII. 

TALLOWING. 

The  hides  are  impregnated  with  tallow  in  the  store¬ 
room,  and  the  tallow  is  melted  in  a  boiler  capable  of 

Fig.  156. 


TALLOWING. 


523 


containing  170  lbs.  This  boiler  is  20  inches  deep  and 
35  inches  in  diameter,  and  is  imbedded  in  the  masonry 
of  the  furnace. 

In  the  middle  of  the  store-room  is  a  stove,  massive, 
square,  and  large  enough  to  put  on  it  an  iron  grate  3 
feet  square;  the  object  of  this  grate  is  to  support  the 
lighted  coal  destined  to  heat  the  room. 


Fig.  157. 


A  heating  apparatus  has  been  proposed  by  Mr.  Curan- 
deau.  It  consists  of  an  oval-shaped  stove  2  feet  high 
and  3  feet  in  diameter.  The  interior  consists  of  a  cast- 
iron  hearth,  paved  at  the  bottom  with  bricks,  and  adapt¬ 
ed  for  burning  wood.  The  smoke  and  heat  ascend 
through  a  pipe  2  feet  long  and  5  inches  in  diameter,  and 
are  conducted  into  a  vertical  pipe  3  feet  high  and  11 
inches  diameter.  From  the  top  of  this  two  smaller 
pipes  diverge,  and  are  connected  with  two  other  ver¬ 
tical  columns,  each  two  feet  ten  inches  high  and  nine 
inches  in  diameter,  which  are  placed  at  the  side  of  the 
main  column;  and  with  the  lower  ends  of  these  two 
pipes  a  fourth  horizontal  one,  placed  two  inches  above 
the  top  of  the  stove,  is  connected,  and  into  this  the 
smoke  and  heat  finally  enter;  the  former  to  escape 
through  a  chimney,  and  the  latter  to  be  given  off'  to  the 
air  of  the  room. 

In  the  oven  you  suspend  poles  on  which  you  put  the 
leathers  to  warm  them.  On  both  sides  are  two  large 
tables  used  to  spread  the  hides  when  you  tallow  them. 

When  the  hides  are  ready  to  be  greased,  fill  the  boiler 
three-quarters  full  with  tallow  and  heat  it  until  melted. 
When  it  has  attained  a  degree  of  heat  a  little  above  the 
melting  point,  it  is  ready  for  use.  If  the  heat  is  too 


524 


HUNGARY  LEATHER. 


great,  the  draught  must  be  lessened  and  lumps  of  cold 
tallow  mast  be  thrown  in.  While  the  tallow  is  being 


Fig.  158. 


M 

s 

s 

— 

mm 

melted,  kindle  a  fire  upon  the  grate  with  a  basketful  of 
charcoal. 

As  soon  as  the  charcoal  is  kindled,  fold  double  24  to 
38  strips  of  hide  according  to  the  size,  stretch  them 
across  the  poles  below  the  ceiling  of  the  room,  placing 
the  largest  and  thickest  the  nearest  to  the  fire.  Then 
the  workmen  leave  the  stove-room,  closing  the  door 
tightly  behind  them,  in  order  to  escape  from  the  stifling 
vapors  proceeding  from  the  hides  and  the  charcoal,  and 
do  not  return  until  they  are  assured  that  the  heating 
has  been  carried  far  enough.  Then  they  air  the  room  a 
little  by  opening  the  door,  enter  in  with  no  clothing  but 
short  aprons,  and  examine  the  leather.  When  suffi¬ 
ciently  warm  they  observe  a  white  appearance,  begin¬ 
ning  at  the  extremities  and  extending  over  the  whole 
surface  of  the  hides.  As  soon  as  this  is  the  case,  they 
remove  the  strips  from  the  poles,  and  stretch  them  out 
upon  each  other,  with  the  flesh  side  uppermost,  on  the 
table  near  the  boiler.  The  thickest  of  the  hides  are 
placed  nearest  to  the  boiler,  and  the  smallest  and  thin¬ 
nest  strips  are  made  to  occupy  the  lowest  position  in  the 
pile. 

Two  men  are  employed  in  tallowing  the  hides.  One, 
the  nearest  to  the  boiler,  takes  off  the  uppermost  strip  of 
the  pile  and  folds  it  double,  with  the  flesh  side  out,  and 
the  head  placed  upon  the  table,  assures  himself  that  the 
tallow  is  heated  to  the  proper  point.  Then  he  takes  a 


TALLOWING. 


525 


tallowing  cloth  or  mop  made  with  pieces  of  rags  or 
blanket  stuffs,  a  foot  long,  and  tightly  tied  around  a 
wooden  handle  six  inches  long,  and,  having 
immersed  it  in  the  boiler  long  enough  for  it 
to  become  saturated  with  the  melted  fat,  rubs 
it  over  the  head  part  of  the  flesh  side  until  the 
half  of  the  surface  is  sufficiently  fed. 

He  is  assisted  by  other  workmen  with  a  similar  mop, 
and  when  half  of  the  leather  is  properly  greased  it  is 
extended  out  at  full  length  by  the  two  workmen,  and 
the  whole  of  the  flesh  side  is  saturated  with  grease. 
Then  the  strip  is  turned  over,  and  the  hair  side  is  greased 
with  the  tallow  still  adhering  to  the  mops,  which  are 
not  dipped  again  in  the  boiler,  for  fear  of  injuring  the 
surface  by  the  heat  of  the  melted  tallow.  When  greased 
throughout,  lay  the  strip  upon  the  table  upon  the 
opposite  side  of  the  room,  with  the  flesh  side  up.  The 
skins  are  in  like  manner  successively  greased  and  piled 
upon  each  other  on  the  table  until  the  end  of  the  opera¬ 
tion. 

It  takes  one  hour  to  prepare  thirty  strips.  Grease  of 
inferior  quality,  such  as  the  residuum  of  melted  tallow 
and  kitchen  stuff,  may  be  employed,  and  about  3  lbs.  of 
it  are  required  for  each  piece  of  leather.  In  the  country 
they  use  sometimes  10  lbs.  of  tallow  for  one  leather,  i.  e., 
5  lbs.  for  each  strip,  but  it  is  useless,  as  the  skin  does 
not  absorb  it  all. 

There  is  no  art  in  which  the  workmen  are  exposed  to 
more  fatigue  and  danger  than  those  they  are  compelled 
to  encounter  while  conducting  the  operations  in  the 
stove-room.  They  constantly  inhale  the  suffocating 
vapors  of  the  skins  and  melted  tallow,  and  the  dangerous 
oxide  of  carbon  given  off  from  the  combustion  of  the 
charcoal ;  they  are  exposed  to  the  risk  of  suffocation  or 
at  least  to  great  irritation  in  the  lungs,  while  the  profuse 
perspiration  of  the  body  predisposes  them  to  take  cold. 
Precautions  must  be  taken  for  them  to  leave  the  room 
immediately  after  the  charcoal  fire  is  lighted,  and  not  re¬ 
enter  it  until  the  atmosphere  has  become  changed  by  a 
current  of  fresh  air  entering  through  the  open  door. 


Fig.  159. 


526 


HUNGARY  LEATHER. 


They  should  not  go  into  the  room  with  full  stomachs, 
bu,t  commence  the  operation  three  or  four  hours  after  a 
meal,  and  in  quitting  work  should  rub  themselves  down 
with  a  coarse  towel  before  resuming  their  dress.  Buz¬ 
zing  or  tinkling  noises  in  the  ear,  giddiness  and  head¬ 
ache,  are  regarded  as  premonitors  of  the  dangerous  effects 
of  the  inhalation  of  oxide  of  carbon,  and  upon  the  occur¬ 
rence  of  this  the  men  should  immediately  leave  their 
work  and  go  into  the  fresh  air. 


CHAPTER  CXLIX. 


FLAMING. 


Leave  the  hides  for  a  time  to  absorb  the  tallow  with 
which  they  have  been  impregnated,  and  cover  them 
with  cloth  in  order  to  prevent  the  unequal  action  of  the 
fire  upon  them.  Then  kindle  a  fire  upon  the  grate  with 
a  basketful  of  charcoal,  leave  the  room,  and  after  a  lapse 
of  half  an  hour,  open  the  door  to  allow  the  gas  to  escape. 
The  charcoal  being  in  full  combustion,  two  men  enter, 
take  the  uppermost  strip  off  the  pile,  one  by  the  head, 
the  other  by  the  tail,  stretch  it  in  every  direction  over 


Fig.  160. 


the  fire  with  the  flesh  side  down,  and  continue  this  for 
about  one  minute.  They  extend  the  strip  upon  the 
empty  table,  the  flesh  side  up,  and  repeat  the  same  ope-, 
ration  with  the  other  strips.  When  the  flaming  is 
finished,  they  cover  the  new  pile  of  hides  with  a  cloth, 
and  leave  it  so  half  an  hour  in  summer,  and  three  hours 


WEIGHING — MARKING — PILING. 


527 


in  winter.  This  operation  is  necessary  for  the  complete 
penetration  of  the  hides  by  tallow.  Some  manufacturers 
light  a  large  fire  in  the  room  and  keep  the  skins  exposed 
to  its  heat,  with  the  door  closed,  for  half  an  hour  or 
more. 


CHAPTER  CL. 

EXPOSURE  TO  THE  AIR. 

After  the  hides  have  remained  in  piles  for  about  three- 
quarters  of  an  hour,  they  are  wiped  on  both  sides  with 
a  dry  rag  or  mop,  to  remove  the  excess  of  grease,  and 
are  hung  in  the  air  upon  poles,  the  flesh  sides  up,  and 
the  heads  and  tails  depending.  They  become  firm  if 
they  are  not  exposed  to  the  direct  influence  of  the  sun. 
In  summer  they  should  be  tallowed  shortly  before  sun¬ 
down,  so  that  when  they  are  aired,  they  need  not  be  ex¬ 
posed  to  the  heat,  but  may  be  cooled  by  the  night  air. 
In  winter  this  precaution  in  unnecessary.  It  is  sufficient 
to  air  during  the  night  in  summer, -and  thirty  hours  in 
winter. 


CHAPTER  CLI. 

WEIGHING.— MARKING.— PILING. 

The  last  operation  consists  in  weighing,  marking,  and 
piling  the  leather.  When  dry,  which  takes  place  in  one 
night  in  summer  and  in  twenty-four  or  thirty  hours  in 
winter,  they  are  piled  and  left  so  for  a  few  days.  A 
hide  thus  manufactured  loses  about  half  of  its  original 
weight,  some  less ;  some  lose  three-fifths,  so  that  a  hide 
which  from  the  butcher  weighed  50  lbs.  is  sometimes 
reduced  to  20  lbs. 

When  the  leather  is  weighed,  mark  the  weight  in 
Roman  characters  on  the  tail,  pile  them  up,  and  a  few 
days  after  they  are  ready  for  the  consumer.  The  room 
in  which  they  are  piled  must  not  be  too  damp  or  too  dry. 
This  leather  can  be  kept  nine  or  ten  months  without 


528 


HUNGARY  LEATHER. 


alteration  in  the  quality,  but  at  last  it  will  lose  of  its 
weight  and  suppleness  and  become  dry  and  hard. 

In  the  summer  season  a  hide  of  leather  can  be  manu¬ 
factured  in  fifteen  days ;  but  in  winter  it  requires  from 
three  wTeeks  to  one  month. 

Fine  Hungarian  leather  is  worth,  in  France,  from 
twenty  to  twenty-two  cents  a  pound ;  a  fine  strip  weighs 
from  twenty-six  to  twenty-eight  pounds,  and  measures 
nine  feet  by  three. 

Alumed  hides  which  have  been  dried  can  be  kept  a 
long  time  without  alteration,  and  it  is  in  that  state  that 
they  must  be  kept  when  it  is  necessary  to  preserve  them 
a  long  time  in  store  after  their  manufacture. 


CHAPTER  CL1I. 

HUNGARY  LEATHER  MADE  OF  COW  AND  CALF-SKINS. 

Occasionally  cow-skins  are  prepared  by  the  Hunga¬ 
rian  method,  but  they  are  depilated  by  liming  instead  of 
scraping.  They  are  left  in  the  lime-pits  until  the  hair 
is  ready  to  come  off,  when  it  is  removed,  and  the  skins 
being  washed  and  scraped  until  the  last  remaining  por¬ 
tions  of  lime  have  been  separated,  are  prepared  in  the 
same  manner  as  thick  hides,  excepting  that  before  being 
tallowed  they  are  not  exposed  for  so  long  a  time  in  the 
stove-room. 

The  liming  renders  them  spongy,  and  disposes  them 
to  absorb  a  larger  quantity  of  alum  and  salt  than  ox¬ 
hides,  in  proportion  to  their  weight. 

Calf-skins  are  prepared  in  the  same  manner,  but  absorb 
much  less  quantities  of  the  materials  used ;  a  large  calf¬ 
skin  requires  about  1  lb.  of  alum,  8  ounces  of  salt,  and 
1  lb.  of  tallow. 


HUNGARY  LEATHER  MADE  OF  HORSE-HIDES.  529 


CHAPTER  GLUT. 

HUNGARY  LEATHER  MADE  OF  HORSE-HIDES. 

These  hides  are  worked  in  the  green  state,  and  to  pre¬ 
vent  the  inequalities  of  surface  which  would  otherwise 
be  found  upon  them,  they  are  not  thoroughly  fleshed, 
but  a  part  of  the  membranous  substance  is  left  upon 
their  flesh  sides.  A  horse-hide,  thus  prepared,  weighs 
30  lbs.  and  used  to  be  sold  for  $1.20  ;  it  is  now  worth 
from  $2.40,  to  $3.00. 

The  hides  are  first  cut  in  half  and  put  to  soak  for  12 
hours,  then  they  are  fleshed  with  a  sickle-shaped  knife, 
and  depilated  by  means  of  lime,  first  for  one  day  in  an 
old  pit,  then  they  are  withdrawn  and  piled  up  for  two 
or  three  days,  when  they  are  put  in  a  second  and  third 
lime-pit  for  three  days. 

When  depilated,  soak  them  12  hours  in  summer  and 
24  hours  in  winter,  occasionally  stirring  in  order  to  re¬ 
move  the  lime.  When  clean,  scrape  them  with  the 
stone,  and  dress  them  upon  the  hair  side  with  the  round 
knife.  Then  roll  them  up  from  head  to  tail,  and  put 
them  aside  to  drain  six  hours. 

They  are  trodden  out  in  the  vats,  like  other  hides, 
with  three  alum  waters,  the  tails  and  manes  being  beaten 
more  forcibly  than  the  other  parts.  A  large  horse-hide 
requires  about  5  lbs.  of  alum  and  21  lbs.  of  salt. 

After  being  stamped,  place  them  in  the  tubs  with 
alum  water,  let  them  remain  in  from  two  to  eight  days, 
and  tramp  them  again  in  the  same  liquors. 

Drain  and  partially  dry  them,  stretch  them  out  with 
the  hands,  dry  them  entirely,  and  work  them  upon  the 
platform  as  ox-hides,  heat  them  upon  the  poles  in  the 
stove-room  for  from  a  quarter  to  half  an  hour,  according 
to  their  degree  of  dryness ;  when  they  are  thus  heated, 
they  give  off  a  vapor  so  offensive  as  to  be  scarcely  endu¬ 
rable. 

Tallow  and  finish  them  in  the  usual  manner.  They 
require  half  the  quantity  of  grease  which  is  used  for  ox- 
34 


530 


HUNGARY  LEATHER.  * 


hides.  The  ordinary  weight  of  a  horse-hide  thus  pre¬ 
pared  is  30  lbs.,  but  they  run  from  14  to  60  lbs. 

This  leather  is  often  mistaken  and  sold  with  that 
prepared  from  ox-hides,  but  it  is  much  inferior  to  the 
latter,  being  apt  to  harden  and  shrink,  and  being  much 
less  firm  and  strong. 

A  few  donkey-hides  are  also  prepared,  but  they  give 
a  bad  leather,  hard,  brittle,  horny,  and  difficult  to  work. 
Their  preparation  is  the  same  as  that  of  other  hides, 
but  they  take  very  little  tallow.  Such  a  hide  is  gene¬ 
rally  sold  for  80  cents,  but  when  prepared,  weighs  from 
6  to  8  lbs.,  and  is  sold  from  15  to  16  cents  a  pound. 


CHAPTER  CLIV. 

M.  KRESSE’S  PROCESS  OF  PREPARING  BLACK  HUNGARY 

LEATHER. 

Mr.  Kresse  took  a  patent  in  1836  for  preparing  black 
Hungary  leather  in  the  following  manner: — 

Take,  when  fresh,  the  hides  intended  to  be  blackened, 
and  spread  over  the  flesh  side  a  mixture  of  orpiment 
and  lime,  and  leave  in  contact  for  two  hours.  Then 
take  the  hair  off,  and  pass  for  some  days  the  hides  in 
baths  of  tan,  alum,  and  salt.  Dry  them  partially ;  soften; 
supple,  and  dry  them.  Grease  them  with  boiling  tallow; 
soak  them  in  water;  stretch  them  upon  the  table,  and 
apply  the  color  on  the  hair  side.  Rub  over  at  first  the 
surfaces  twice  with  stale  urine.  The  third  and  fourth 
applications  consist  of  a  color  made  with  decoctions  of 
three  parts  of  logwood  and  one  part  of  fustic;  the  fifth 
and  sixth  of  alder  bark,  iron  rust,  and  nutgalls,  mixed 
with  lemon-juice.  Being  thus  coated,  dry  the  skins, 
and  smooth  them  by  stretching  upon  the  table. 

To  make  the  color  of  the  last  two  applications:  Squeeze 
100  spoiled  lemons  into  a  bucketful  of  broken  pieces  of 
alder  bark,  mixed  with  10  lbs.  of  scraps  of  rusty  iron 
and  1  lb.  of  bruised  nutgalls.  Stir  up  the  contents  of 
the  bucket,  and  leave  for  fifteen  days,  at  the  end  of  which 
time  the  liquid  is  poured  out  and  ready  for  use.  Some- 


DEFECTS  IN  THE  QUALITY  OF  HUNGARY  LEATHER.  531 

times  the  skins  become  mouldy  before  being  colored  if 
they  are  piled  in  a  moist  place ;  and,  in  order  to  prevent 
this  occurrence,  prepare  them  in  the  following  man¬ 
ner  : — 

Wash  them  in  the  river,  and,  before  being  alumed 
place  them  in  a  vat,  and  cover  them  with  warm  water, 
with  which  a  bushel  of  bran  and  four  ounces  of  ferment 
have  been  previously  mixed,  steep  them  three  days  in 
this  bath,  and  alum  them  ;  tread  them  out  three  times 
in  warm  water  to  remove  the  salt,  and  dry  them. 

To  give  the  skins  a  brown  color,  similar  to  that  of 
tanned  leather,  steep  them  for  a  few  days  in  tan  liquor. 
If  it  is  desired  to  blacken  them,  they  may  then,  after 
receiving  the  four  first  dressings  mentioned  above,  be 
brushed  over  twice  on  the  hair  side  with  a  solution  of 
copperas  instead  of  the  mixture  prepared  with  lemon- 
j  uice. 


CHAPTER  CLV. 

DEFECTS  IN  THE  QUALITY  OF  HUNGARY  LEATHER. 

The  causes  of  these  defects  have  several  different 
springs.  Generally  a  bad  skin  will  not  make  a  good 
leather,  whatever  is  the  process.  In  the  art  of  tanning 
we  have  indicated  the  signs  to  recognize  a  skin  of  bad 
quality,  and  the  cuts  made  by  butchers  are  the  greatest 
trouble  in  the  preparation  of  this  kind  of  leather. 

We  have  said  before,  that  horse-hides  must  be  used 
immediately  after  the  animal  has  been  killed ;  and  this 
precaution  must  not  be  neglected,  for  if  the  skins  expe¬ 
rience  a  beginning  of  fermentation  the  hair  side  loses  its 
consistency. 

Leather  imperfectly  tramped  during  the  aluming  pro¬ 
cess,  or  which  has  been  treated  only  with  two  or  three 
waters,  cannot  be  properly  worked  upon  the  platforms. 
It  will  not  absorb  as  much  tallow  as  is  necessary,  and  is 
apt  to  contain  horny  and  hard  portions,  which  diminish 
its  strength.  The  hides,  which  have  spots  of  extrava- 
sated  blood  upon  their  surfaces,  should  be  rejected  as 
being  weak  and  of  bad  quality. 


532 


HUNGARY  LEATHER. 


CHAPTER  C  L  VI. 

USES  OF  HUNGARY  LEATHER. 

This  leather  is  particularly  used  by  collar  and  harness- 
makers,  who  employ  it  for  harness  and  main  braces  of 
coaches.  For  the  latter,  according  to  Dessables,  they 
take  the  strongest  leather  and  put  five  or  six  strips  one 
on  the  other.  After  being  sewed  together,  they  are 
covered  with  curried  cow-hide.  Hungarian  leather  is  the 
only  one  to  which,  in  France,  suppleness  is  given  by 
tallow,  but  in  some  parts  of  Italy,  they  tallow  leathers 
even  destined  for  soles. 

The  tallowing  is  the  most  difficult  operation.  Too 
much  heat  renders  the  leather  brittle ;  not  enough,  it 
does  not  absorb  the  tallow  well.  If  the  tallow  is  too 
hot,  it  burns  the  leather ;  if  not,  it  does  not  penetrate. 
The  difficulty  is  to  operate  at  the  right  time. 

The  tallowing  is  very  important,  for  if  it  has  not  suc¬ 
ceeded,  it  cannot  be  done  over,  for  the  tallow  will  not 
penetrate  well,  and  the  leather  takes  a  blackish  color. 


CHAPTER  CLVII. 

IMPROVEMENT  OF  M.  CURANDEAU.* 

Curandeau,  believing  that  the  change  experienced  by 
the  skins  in  the  bath  of  alum  and  salt  is  due  chiefly  to 
the  excess  of  sulphuric  acid,  proposed  the  substitution 


of  this  acid  for  alum. 

Consequently  he  prepares  the 

following  bath : — 

Water 

.  .  .  .  25  gallons 

Salt  .... 

.  ,  .  .  20  pounds 

to  which  he  adds 

Sulphuric  acid  . 

4  lbs. 

The  skins,  after  passing  through  the  preliminary  pro¬ 
cesses,  are  macerated  in  this  bath,  and  after  a  maceration 


*  Memoire  de  l’Academie  des  Sciences. 


IMPROVEMENT  OF  M.  CURANDEAU. 


533 


of  twenty-four  hours  they  are  withdrawn  and  dried. 
As  much  progress  is  made  by  the  skins  in  this  bath  in 
twenty-four  hours  as  by  those  which  are  exposed  for  a 
much  longer  time  in  the  bath  previously  given,  and  they 
possess  all  the  best  qualities  of  Hungary  leather. 

The  advantages  of  this  process  are  the  following : — 

1.  It  requires  only  two  parts  of  acid,  the  price  of 
which  is  lower  than  alum. 

2.  This  bath  does  not  require  to  be  as  warm  as  alum. 

3.  The  manipulations  are  much  shorter  than  by  the 
use  of  the  salt  bath. 


PART  y. 


GUT  DRESSING. 

The  art  of  the  gut  dresser  consists  in  separating  the 
middling  or  muscular  coat  of  the  intestines  of  certain 
animals  from  its  external  or  peritoneal  covering,  and 
from  its  internal  lining  or  mucous  membrane,  and  may 
be  divided  into  two  distinct  branches ;  the  preparation 
of  the  intestine  of  oxen  and  cows  for  the  preparation  of 
alimentary  substances,  and  that  of  the  intestines  of  sheep 
for  the  manufacture  of  cords  for  various  purposes. 


SECTION  XIII. 

PREPARATION  OF  THE  INTESTINES  OF 

CATTLE. 


The  intestines  are  submitted  to  the  eleven  following 
operations,  which  will  be  described  in  the  order  as  be¬ 
low: — 


1.  Scouring. 

2.  Turning  over. 

3.  Putrid  fermentation. 

4.  Scraping. 

5.  Washing. 

6.  Insufflation. 


7.  Desiccation. 

8.  Pisinsufflation. 

9.  Measuring. 

10.  Sulphuration. 

11.  Folding. 


CHAPTER  CLVIII. 

OPERATIONS  FOLLOWED  IN  THE  PREPARATION  OF 
INTESTINES  OF  CATTLE. 

Description  of  the  Workshop. — The  workshop  of  the 
gut  dresser  consists  of  a  room  twenty  feet  long,  sixteen 


PREPARATION  OF  INTESTINES  OF  CATTLE. 


535 


feet  wide,  and  twelve  feet  high,  with  four  windows  ;  these 
windows  are  opened  or  shut  according  to  the  seasons. 
Around  the  sides  of  the  room  are  ranged  casks  of  about 
sixty  gallons  capacity,  and  in  the  middle  of  the  ground 
are  fixed  wooden  stakes  for  attaching  hooks.  The 
remnants  of  the  intestines  are  usually  allowed  to  lie 
about  the  floor,  and  they  exhale  an  odor  which,  with  that 
from  the  putrefying  intestines  in  the  tubs,  is  the  most 
disgusting  that  can  be  conceived,  and  is  so  permanent 
that  the  clothes  of  the  workmen  remain  for  a  long  time 
impregnated  with  it.  Usually  a  well  is  sunk  in  a  yard 
attached  to  the  building  for  receiving  the  waste  matters 
of  the  factory. 

I.  Operation. — Scouring.  As  soon  as  the  small  in¬ 
testines  of  oxen  and  cows  are  brought  from  the  slaughter¬ 
house  to  the  workshop  they  are  steeped  in  water,  in 
order  to  moisten  and  smooth  the  surfaces,  so  that  the 
knife  may  slide  easily  over  them.  When  this  is  done, 
an  end  of  one  the  intestines  is  attached,  by  tying  it  in  a 
kind  of  knot  around  a  hook,  to  one  of  the  stakes  in  the 
centre  of  the  room  at  a  height  of  six  or  seven  feet  above 
the  ground.  The  workman  then  grasps  the  depending 
portion  between  the  thumb  and  first  finger  of  the  left 
hand,  and  gradually  slides  the  hand  down  along  the  whole 
length  of  the  intestine,  follows  its  motion  by  passing  a 
knife,  held  in  the  right  hand,  over  the  surface,  so  as  to 
separate  the  fat  and  as  much  as  possible  of  the  outer  or 
peritoneal  coat. 

Another  portion  of  gut  is  then  treated  in  the  same 
way,  and  the  operation  is  continued  until  all  the  con¬ 
tents  of  the  casks  have  been  cleaned. 

If  any  parts  of  the  intestines  have  been  scratched  or 
divided  by  the  butchers  in  separating  the  fat,  these  are 
cut  olf  and  thrown  aside. 

The  fat  falling  to  the  ground  is  separated  from  the 
feculent  and  other  matters,  and,  after  being  washed  a 
number  of  times,  is  dried,  melted,  and  rendered. 

II.  Operation: — Turning  Over.  The  intestines  are 
next  washed  in  a  large  cask  half  full  of  water,  and  the 
workman  proceeds  to  turn  them  inside  out,  by  introduc- 


536 


GUT  DRESSING. 


ing  a  thumb  into  the  interior  of  each,  and  working  the 
gut  upon  it  with  the  fingers  until  the  whole  is  inverted. 

A  number  of  the  pieces  are  then  tied  together  at  their 
ends  with  a  cord  which  is  attached  to  the  edge  of  the 
cask,  and  when  a  sufficient  number  of  inverted  intestines 
are  thus  fastened,  they  are  left  with  only  their  original 
contents  of  water  to  undergo  the  next  operation. 

III.  Operation. — Putrid  Fermentation.  Experience 
alone  can  guide  the  workman  in  determining  when  putre¬ 
faction  is  sufficiently  established.  It  should  be  carried 
only  far  enough  to  disorganize  the  mucous  membrane 
and  other  parts  which  are  to  be  separated  from  the 
middle  coat  of  the  intestines,  and,  if  allowed  to  advance 
too  far,  the  whole  tissue  will  be  softened  and  rendered 
useless. 

In  summer,  two  or  three  days  of  exposure  are  suffi¬ 
cient,  and  it  requires  from  five  to  eight  in  winter.  The 
putrefaction  is  known  to  have  reached  the  proper  stage 
when  bubbles  of  gas  begin  to  escape  from  the  surface  of 
the  intestines.  This  operation  is  a  most  disgusting  one, 
but  it  does  not  seem  to  be  injurious  to  the  health  of  those 
working  in  the  room. 

IV.  Operation. — Scraping.  When  sufficiently  rolled, 
the  pieces  are  untied,  soaked  in  a  cask  half  full  of  water, 
and  the  next  operation  consists  in  separating  the  dis¬ 
organized  mucous  lining,  which  is  now  upon  the  outside. 
This  the  workman  proceeds  to  effect  by  scraping  it  off 
with  his  thumb-nails  until  it  is  entirely  detached.  The 
operation  is  facilitated  by  frequently  dipping  the  pieces 
in  water. 

V.  Operation. — Washing.  The  intestines  are  in¬ 
troduced  into  tubs  full  of  pure  water,  and  they  are 
stirred  several  times  every  day.  The  water  is  changed 
two  or  three  times  a  day,  and  the  operation  is  continued 
until  the  water  comes  from  them  unclouded  and  free 
from  taint. 

VI.  Operation. — Insufflation.  When  the  intestines 
are  perfectly  cleaned,  one  end  of  each  piece  is  tied  with 
a  string,  and  the  workman  introduces  into  the  other 
orifice  a  hollow  cylinder  of  cane,  angle,  or  reed,  about 


PREPARATION  OF  INTESTINES  OF  CATTLE. 


537 


five  inches  long,  and  after  making  the  joint  air-tight  by 
pressing  the  rim  of  the  gut  tightly  around  it,  applies  his 
mouth  to  the  end,  and  expands  the  gut  by  blowing  into 
it  and  then  closes  the  orifice,  tying  it  tightly  with  a  cord. 
If  holes  are  found,  the  intestine  is  cut  off  at  the  place 
where  they  occur,  and  tied  again  with  a  cord. 

VII.  Operation. — Desiccation.  When  all  the  pieces 
are  thus  filled  with  air,  they  are  carried  to  the  drying 
place,  and  are  laid  out,  so  as  not  to  be  in  contact  with 
each  other,  upon  horizontal  poles  placed  about  five  feet 
from  the  ground,  and  left  until  dried. 

VIII.  Operation.-— Disinsufflation.  When  perfectly 
dry,  the  pieces  are  taken  down,  cut  across  with  scissors 
as  near  the  ligatures  as  possible,  then  they  are  pressed 
and  flattened  with  the  hand  so  as  to  expel  all  the  air 
contained  in  them. 

IX.  Operation. — Measuring.  They  are  then  assorted 
into  different  sizes,  according  to  the  purpose  for  which 
they  are  intended ;  they  are  collected  into  bundles  and 
hung  in  a  damp  place  preparatory  to  be  sulphuretted. 

X.  Operation. — Sulphur ation.  After  being  kept  in 
a  damp  place  for  some  time,  the  intestines  are  exposed 
to  the  vapors  of  sulphur  in  a  room  five  feet  square  and 
61  feet  high.  For  this  purpose  they  are  strung  on  sticks, 
and  if  not  sufficiently  moist  when  introduced  into  it, 
they  are  sprinkled  over  with  water  from  a  brush,  and 
are  then  suspended  across  the  upper  part  of  the  cham¬ 
ber  to  the  number  of  a  hundred  bundles.  A  pound  or 
more  of  flowers  of  sulphur  is  then  put  in  an  earthen 
dish  on  the  floor  of  the  room,  and  ignited  by  burning 
coals  thrown  upon  it.  The  door  is  immediately  closed, 
and  the  further  precaution  to  prevent  the  escape  of  va¬ 
pors  being  taken  of  luting  it  around  the  edges,  and  of 
gluing  stout  pieces  of  paper  upon  any  apertures  which 
exist  in  the  room. 

XI.  Operation. — Folding.  At  the  end  of  some  hours, 
open  the  door  of  the  room  and  allow  the  vapors  to  escape. 
The  intestines  which  have  been  thus  exposed  are 
bleached,  deprived  of  their  bad  odor,  and  are  protected 
against  the  attacks  of  insects. 


538 


GUT  DRESSING. 


While  still  damp  they  are  twisted  into  hanks,  packed 
with  camphor  and  sent  to  market. 


CHAPTER  CLIX. 

DISINFECTION  OF  THE  WORK-SHOPS.  MODE  OF 
SUPPRESSING  PUTREFACTION. 

In  order  to  prevent  the  offensive  smell  arising  from 
the  putrefaction  of  intestines,  the  following  process  of 
separating  the  mucous  membrane  has  been  devised  by 
Labarraque.  * 

The  small  intestines  of  fifty  cattle  which  have  been 
cleaned  and  turned  inside  out  are  mixed  in  a  cask  with 
two  pailfuls  of  water,  each  containing  I2  lb.  of  chloride 
of  potash  at  12  or  13°,  and  if  there  is  not  enough  liquid 
to  cover  them,  another  pailful  of  fresh  water  is  added. 

The  whole  is  stirred  about,  well  mixed,  and  left  over 
night.  The  membrane  can  be  detached  as  easily  the 
next  day,  as  after  many  days  of  putrefaction  in  the  usual 
method,  and  the  unpleasant  odor  is  entirely  avoided. 

The  succeeding  operations  are  performed  in  the  same 
manner. 


CHAPTER  CLX. 

GOLD-BEATER’S  SKIN. 

This  skin  is  prepared  from  the  external  or  peritoneal 
coat  of  the  caecum  or  blind  gut  of  neat  cattle.  The 
workman  separates  and  turns  over  the  portion  which 
encircles  the  junction  of  this  pouch  with  the  rest  of  the 
intestines,  and  draws  it  off  inverted  from  the  other  coats 
to  the  length  of  25  or  30  inches.  It  is  then  immersed 
a  short  time  in  a  weak  solution  of  potash,  and  is  cleaned 
by  scraping  upon  a  board  with  a  knife.  When  thus 
well  cleaned,  and  by  soaking  in  water,  the  piece  is 
stretched  upon  a  kind  of  frame  from  40  to  50  inches  in 
length  and  11  inches  wide,  and  made  of  two  uprights 
held  together  by  two  cross-pieces  having  longitudinal 


LATHE- CORDS. 


539 


grooves,  two  and  a  half  lines  in  width.  The  surface  of 
the  membrane,  which  was  outside  in  the  animal,  is  placed 
in  contact  with  the  upper  part  of  the  frame ;  it  is 
stretched  in  every  direction,  and  is  glued  to  its  rim. 
Another  membrane  is  then  stretched  above  the  first 
with  its  external  surface  placed  upwards  and  is  attached 
to  it  by  gluing  around  the  edges.  When  dry,  the  mem¬ 
branes  are  separated  by  running  a  sharp  knife  along  the 
grooves.  Each  strip  is  then  glued  upon  a  frame  similar 
to  the  first  one,  but  without  a  groove,  and  is  washed 
over  with  a  solution  composed  of — 

Alum,  1  ounce. 

,  Water,  2  quarts. 

When  the  surface  is  dried,  pass  over  it  a  sponge  dipped 
in  a  concentrated  solution  of  fish-glue  in  white  wine, 
rendered  aromatic  by  cloves,  nutmegs,  or  camphor, 
When  this  coating  is  dried,  cover  it  with  a  coat  of 
white  of  eggs,  and  the  strip  is  cut  into  pieces  5  2  inches 
square,  which  are  then  smoothed  out  under  a  press,  and 
made  up  into  leaves. 


CHAPTER  CLXI. 

LATHE-CORDS. 

These  cords  are  made  of  intestines  of  horses,  cleaned 
and  prepared  by  the  separation  of  the  mucous  membrane 
in  the  manner  before  described.  A  wooden  ball,  armed 
in  its  lower  part  with  four  cutting  blades,  at  equal  dis¬ 
tances  from  each  other,  is  fixed  by  an  upright  piece  of 
wood  to  a  bench.  The  end  of  an  intestine  is  then  drawn 
over  this  ball,  and  as  the  gut  is  pulled  downwards  it  is 
divided  into  four  equal  bands  or  strips. 

Four  or  eight  of  these  strips,  according  to  the  thick¬ 
ness  which  it  is  intended  to  give  to  the  cord,  are  tied 
with  a  peculiar  knot  to  one  end  of  a  thick  piece  of  cord. 
The  end  is  passed  around  a  peg  introduced  into  a  hole 
in  a  solid  post,  to  the  side  of  which  a  number  of  pegs  are 
attached.  At  a  distance  of  ten  or  eleven  yards  from 


540 


GUT  DRESSING. 


the  first  one,  another  post  is  fixed,  similarly  provided 
with  pegs,  and  over  one  of  these  latter  the  middle  of  the 
assemblage  of  strips  is  passed,  the  other  end  being 
brought  back,  and  attached  to  the  first  peg  by  means  of 
another  knotted  cord.  The  tied  ends  of  the  strips  are 
then  attached  to  the  wheel  by  a  hook  connected  with 
the  whirl ,  which  is  made  to  revolve  until  the  strips  are 
sufficiently  twisted.  The  twisted  end  is  then  kept 
stretched  by  attaching  it  to  the  peg,  and  any  projecting 
filaments  are  cut  off.  After  being  stretched  for  some 
time,  the  cords  are  then  twisted  again,  and  a  third  and 
a  fourth  time  are  twisted  by  hand,  being  each  time 
rubbed  with  and  drawn  through  a  bunch  of  moistened 
horse-hair  after  the  twisting,  and  again  stretched  out 
between  the  two  posts.  If  the  cord  is  not  smooth  and 
even  after  the  twisting  is  completed,  it  is  made  so  by 
rubbing  with  a  piece  of  dog-skin.  It  is  then  dried,  and 
by  some  makers  is  exposed  to  the  vapors  of  sulphur. 
At  last  the  ends  are  cut  off,  and  the  cord  is  rolled  in  a 
coil. 

In  order  to  avoid  the  putrid  emanations  from  the  in¬ 
testines,  which  are  generally  in  an  incipient  state  of  de¬ 
composition,  Labarraque  recommends  to  clean  them  at. 
once ;  turn  the  inside  out,  and  put  to  soak  over  night 
in  a  cask  containing,  for  fifteen  or  twenty  intestines” 

Chloride  of  potash  at  13  or  18°,  1  lb. 

Water,  4  galls. 

The  mucous  membrane  is  ready  to  be  detached  the 
next  day ;  and  after  its  removal,  and  a  thorough  wash¬ 
ing,  the  intestines  can  at  once  be  prepared  as  has  been 
already  described. 


CHAPTER  CLXII. 

MANUFACTURE  OF  CORDS  FROM  THE  INTESTINES  OF 

SHEEP. 

Remove  the  intestines  from  the  body  of  the  animal 
when  warm,  clean  and  free  them  from  fecal  matter,  and 


COEDS  FROM  THE  INTESTINES  OF  SHEEP. 


541 


carry  them  to  the  workshop.  If  they  are  not  perfectly 
clean,  and  if  decomposition  has  been  allowed  to  com¬ 
mence,  they  are  strained  so  as  to  be  unfit  for  most  of  the 
purposes  for  which  they  are  intended. 

They  are  unravelled  and  deprived  of  adhering  fat 
while  soaking  in  a  tub  of  water  ;  then  they  are  placed 
in  fresh  water,  and  the  small  ends  of  the  intestines  are 
tied  together,  and  laid  on  the  edges  of  the  tub,  while 
their  bodies  are  left  to  steep  for  two  or  three  days  in 
water  which  is  frequently  changed.  The  removal  of 
the  mucous  and  peritoneal  coats  is  facilitated.  After 
this,  the  intestines  are  placed  upon  a  bench,  which  slopes 
down  towards  the  edge  of  the  tub,  and  the  surface  is 
scraped  with  the  back  of  a  knife  blade  in  order  to 
separate  and  remove  the  external  membranes,  in  breadth 
of  about  half  of  the  circumference.  The  filandre  (the 
coating)  can  only  be  freely  removed  in  pieces  of  the 
proper  size  and  length  by  pulling  it  off  in  the  direction 
from  the  small  to  the  large  end  of  the  intestine.  It  is 
employed  as  thread  to  sew  intestines,  and  to  make  the 
cords  of  rackets  or  battledores.  In  the  event  of  its 
breaking,  the  separated  pieces  must  be  tied  together, 
and  they  are  laid  aside  with  the  others  for  use. 

The  guts  are  then  soaked  in  fresh  water  for  twenty- 
four  hours,  and  are  taken  out  and  scraped  clean  upon 
the  bench  with  the  back  of  a  round-bladed  knife.  About 
eight  feet  of  the  larger  ends  are  now  cut  off  and  sold  to 
the  sausage  makers.  The  rest  are  then  cut  of  a  proper 
length,  and  are  imbedded,  as  it  were,  between  layers  of 
salt.  Alternating  heaps  of  intestines  and  layers  of  salt 
are  packed  in  until  all  the  intestines  have  been  salted. 
Some  days  after,  remove  and  pack  them  with  a  small 
quantity  of  salt,  so  as  to  be  ready  at  any  time  for  the 
following  process. 

After  the  curing  process  is  completed,  take  out  the 
intestines,  and  soak  them  over  night  in  fresh  water,  and 
deposit  them  the  following  day  in  a  lye  made  with— - 

Pearlash  .....  8  ounces 

Water  ......  4  galls. 

The  strength  of  the  lye  is  determined  by  the  experience 


542 


GUT  DRESSING. 


of  the  workman.  Pour  the  lye  in  successive  quantities 
upon  the  intestines,  and  pour  it  off  again  every  two  or 
three  hours  until  they  have  been  sufficiently  acted  upon. 
Then  draw  them  two  or  three  times  through  an  open 
brass  thimble,  and  press  against  it  with  the  nail  in  order 
to  scrape  off  unnecessary  and  projecting  parts  from  the 
surfaces,  after  which  they  are  selected  for  different  pur¬ 
poses  according  to  their  size. 


CHAPTER  CLXIII. 

DIFFERENT  CORDS. 

Cords  for  Backets. — These  cords  are  generally  made 
of  intestines  of  inferior  quality,  or  which  have  been 
stained  by  commencing  putrefaction.  The  pieces,  while 
still  moist,  are  sewed  together  with  strips  of  the  outer 
membranes  or  flandre,  each  junction  being  cut  aslant  so 
as  to  make  it  smooth  and  strong. 

Three  of  four  of  these  intestines  are  thus  attached  by 
strings  to  the  whirl,  and  are  twisted  in  the  usual  way ; 
after  which  the  cord  is  smoothed  and  deprived  of  mois¬ 
ture  by  the  hand  of  the  workman,  and  is  left  stretched 
for  a  time.  It  is  again  twisted  and  rubbed  with  a  bunch 
of  horse-hair.  The  inferior  kinds  of  cords  are  made  by 
twisting  one  gut  along  with  two  or  three  pieces  of  the 
filandre. 

Whip-cords  are  made  of  intestines  of  good  quality, 
prepared,  cut,  and  sewed  as  described.  Each  end  is 
twisted  separately,  as  whip-cords  are  seldom  made  of  two 
intestines  sewed  together.  Sulphur  the  cord  once  or 
twice,  and  dy^  it  black  with  common  ink,  or  of  a  rose 
color  with  red  ink,  which  the  sulphurous  acid  turns  to 
a  pink  color,  or  with  a  green  dye.  Dry  and  smooth  the 
cords,  and  coil  them  up  into  suitable  sizes  for  sale. 

Hatted  s  Cords  for  j Bowstrings. — These  cords  are  usually 
from  sixteen  to  twenty-eight  feet  long ;  they  are  made 
by  twisting  the  longest  and  largest  intestines  of  sheep, 
four,  six,  eight,  ten,  twelve  being  put  together  according 
to  the  intended  size. 


CORDS  FOR  MUSICAL  INSTRUMENT  STRINGS. 


543 


Tlieir  preparation  requires  more  care  than  that  of 
those  which  have  been  described  before,  and  it  must  be 
perfectly  free  from  seams  and  knots.  Twist  them  with 
the  wheel  in  the  usual  way,  and  stretch  them  well  and 
smooth  them  after  each  operation.  When  partially 
dried  expose  them  twice  to  the  vapors  of  burning  sulphur, 
then  rub  them  well  with  a  bunch  of  horse-hair  rope 
dipped  in  potash  lye ;  dry  them  while  in  a  state  of  ten¬ 
sion,  cut  off,  and  coil. 

Clock-maker’s  Cord. — This  kind  differs  from  the  other 
in  being  extremely  thin.  It  is  made  of  intestines  of  the 
smallest  size,  or  of  strips  made  by  dividing  each  gut  into 
two  pieces  by  drawing  it  down  over  a  kind  of  lancet 
mounted  upon  a  leaden  or  wooden  ball,  which  guides 
the  blade,  the  two  sections  of  the  gut  falling  into  a 
vessel  placed  beneath.  Sometimes  clock-makers  use 
cords  of  larger  diameter  made  of  two  or  more  intestines. 


CHAPTER  CLXIY. 

CORDS  FOR  MUSICAL  INSTRUMENT  STRINGS. 

These  strings  should  be  of  uniform  diameter,  perfectly 
smooth,  round,  and  free  from  ^shreds  and  filaments. 
They  should  be  as  little  liable  as  possible  to  stretch  or 
break,  and  should  preserve  their  polish  and  transparency 
during  all  the  changes  of  weather.  Their  manufacture 
requires  great  experience  and  dexterity.  The  best 
strings  have  been  made  from  time  immemorial  in  Italy, 
and  although  some  of  superior  quality  are  manufactured 
in  France,  the  preparation  of  treble  strings  is  confined 
to  Naples.  The  membranes  of  lean  animals  are  well 
known  to  be  much  more  tough  than  those  of  animals  in 
high  condition,  and  the  superior  quality  of  the  strings 
made  at  Naples  is  attributed  in  a  measure  |o  the  small¬ 
ness  and  leanness  of  the  sheep  in  its  vicinity. 

The  guts  intended  for  these  strings  are  first  very  care¬ 
fully  scraped.  Then  dissolve  in  six  pailfuls  of  water 
three  pounds  of  potash,  and  mix  with  the  same  quantity 
of  water  five  pounds  of  pearlash,  clarify  the  solution  by 


544 


GUT  DRESSING. 


adding  to  it  a  little  alum.  Keep  the  two  solutions  in 
stoneware  vessels.  Then  half  fill  stoneware  pans  with 
the  intestines,  and  pour  in  the  potash  liquor,  mixed 
with  an  equal  quantity  of  water,  until  the  vessels  are 
full. 

Steep  the  intestines  three  or  four  days,  and  even 
longer,  changing  the  solutions  twice  daily,  and  making 
them  progressively  stronger  by  adding  each  time  some 
of  the  ash  lye  and  diminishing  the  quantity  of  water 
mixed  with  it.  Each  time  that  the  solution  is  changed, 
the  intestines  are  removed  from  the  vessel  and  are  re¬ 
placed,  after  draining  upon  a  sloping  table,  and  after 
being  passed  through  a  thimble  in  the  manner  before 
described.  The  effect  of  the  alkaline  solution  is  to 
bleach  and  swell  the  intestines,  and  they  must  be 
removed  from  it  at  the  first  appearance  of  little  bubbles 
of  gas  escaping  from  them,  or  they  will  be  rendered  unfit 
for  use.  This  occurs  oftener  in  summer  than  in  winter. 

After  being  passed  through  the  thimble  so  as  to 
smooth  and  equalize  their  surface,  and  washed  in  fresh 
water,  the  intestines  are  attached  to  the  frame  in  order 
to  be  twisted.  This  frame  is  five  feet  three  inches  long 
and  twenty-five  inches  broad.  A  number  of  pegs  are 
fixed  in  one  of  its  sides,  and  a  double  number  of  holes 
are  bored  through  the  other  side,  so  that  the  cords  passed 
through  them  are  kept  in  place  when  pegs  are  introduced. 
The  ends  of  the  intestines  are  first  placed  together  upon 
the  edge  of  the  tub  in  which  they  have  been  soaked,  and 
two  or  three  or  more  of  the  same  diameter  and  length 
are  selected  and  fixed  to  one  of  the  double  holes  by 
means  of  a  peg,  and  the  bodies  of  the  intestines  are  then 
drawn  out  exactly  of  the  same  length  and  brought  over 
the  corresponding  large  pegs  on  the  opposite  side  of  the 
frame,  the  ends  being  carried  back  and  fixed  in  the  other 
one  of  the  two  holes.  If  some  of  the  intestines  are  not 
sufficiently  long  to  stretch  across,  they  are  sewed  to  other 
pieces  as  near  as  possible  to  the  end  of  the  cord,  so  that 
the  points  may  be  near  the  extremity  of  the  string,  and 
may  not  interfere  with  the  uniformity  of  surface  of  its 
main  part.  The  intestines  are  then  twisted  on  the  hooked 


CORDS  FOR  MUSICAL  INSTRUMENT  STRINGS. 


545 


wheel  in  the  ordinary  manner,  and  are  exposed  for  two 
or  three  hours  in  the  sulphuring  room,  after  which  they 
are  forcibly  rubbed  with  the  horse-hair  rope  and  twisted 
and  rubbed  again.  They  are  again  exposed  to  the  vapor 
of  burning  sulphur,  twisted  once  more  and  sulphuretted 
for  a  third  time,  after  which  they  are  left  to  dry  in  a 
state  of  tension. 

The  strings  are  known  to  be  sufficiently  dried  when 
one  of  the  strands,  upon  being  removed  from  its  peg, 
shows  no  tendency  to  turn,  but  remains  in  the  straight 
position  in  which  it  is  held.  When  the  strings  have 
arrived  at  this  degree,  they  are  rubbed  over  with  olive 
oil,  cut  off  at  the  ends,  and  coiled  up. 

The  fourth  strings  of  violins,  which  are  wrapped  in 
wire,  are  neither  sulphuretted  nor  oiled.  The  string 
intended  to  be  wrapped  is  cut  off  the  length  of  one  and 
a  quarter  yards,  and  one  of  its  ends  is  attached  to  the 
hook  of  the  wheel,  and  the  other  to  the  ring  of  a  whirl, 
which  keeps  the  string  stretched  by  means  of  a  weight 
at  the  end  of  a  cord  fastened  to  it  and  passing  over  a 
pulley.  The  wire  is  then  fastened  around  the  string 
close  to  the  whirl,  and  as  the  wheel  is  made  to  revolve, 
the  string  and  the  whirl  turn  with  it.  The  workman 
supports  the  string  with  his  left  hand,  and  the  wire  pass¬ 
ing  through  his  right  hand  is  made  to  revolve  around  it 
in  close  spiral  turns  until  it  is  entirely  and  equally 
covered. 

As  has  been  before  observed,  the  utmost  care  and  skill, 
on  the  part  of  the  workman,  are  required  for  the  manu¬ 
facture  of  harp  or  violin  strings  of  good  quality.  His 
experience  alone  will  enable  the  workman  to  conduct 
the  different  operations  with  the  requisite  dexterity. 


35 


PART  VI. 


DIFFERENT  KINDS  OF  APPARATUS  USED 
BY  LEATHER  MANUFACTURERS. 


CHAPTER  Cl vXV. 

IMPROVED  MACHINE  FOR  ROLLING  GREEN  OR  WET 
LEATHER.* 

Mr.  J.  Whitney,  of  Winchester,  Mass.,  has  invented 
a  new  and  useful  improvement  in  machinery  for  treating 
green  or  wet  leather,  so  as  to  express  the  water  or  tan¬ 
ning  liquor  from  the  same,  and  not  discolor  the  surface 
thereof.  The  following  is  an  explanation  of  his  patented 
machinery. 

Fig.  161. 


Fig.  161  is  a  plan  with  a  portion  of  the  frame  and 
rollers  broken  away  at  the  centre  to  show  the  treadle. 

Fig.  162  is  a  vertical  longitudinal  section  through  the 
centre  of  the  rollers,  showing  an  arrangement  of  levers 
for  relieving  the  pressure. 

*  Patented  by  J.  Whitney,  of  Winchester,  Mass.,  March  24, 1863. 


IMPROVED  MACHINE  FOR  ROLLING  LEATHER.  547 


Fig.  163,  an  end  elevation  of  the  machine. 


Fisr.  16^. 


Fig.  164  is  a  modification  of  the  lever  arrangement. 
Figs.  165,  166,  167,  168,  169,  170  are  details  of  the 
machine.  Similar  letters  of  reference  in  the  figures  in¬ 
dicate  corresponding  parts. 

In  the  process  of  tanning  skins  of  which  thick  leather 


548  APPARATUS  USED  BY  LEATHER  MANUFACTURERS 

Fig.  164. 


Fig.  165. 


is  made,  it  is  necessary  to  split  the  leather  in  order  to 
reduce  the  thickness ;  and  in  order  to  accomplish  the 
splitting  at  certain  stages  of  the  tanning  process,  the 
tanning  liquor  or  water  must  be  expressed  from  it  before 
commencing  the  splitting  operation,  and  in  the  express¬ 
ing  operation,  means  such  as  will  not  discolor  the  surface 
of  the  leather  must  be  employed  because  the  market 
value  is  greatly  affected  by  the  color. 

If  iron  rollers  are  used,  the  tannic  acid  causes  a  cor¬ 
rosion  of  the  metal  and  the  rust  is  imparted  to  the  surface 


Fig.  168. 


Fig.  167. 


IMPROVED  MACHINE  FOR  ROLLING  LEATHER 


549 


Fig.  169. 


Fig.  no. 


of  the  leather,  and  besides  this  the  leather  is  hut  imper¬ 
fectly  operated  upon,  as  the  surface  of  the  rollers  cannot 
conform  to  the  irregularity  of  thickness  of  the  leather, 
nor  is  it  desirable  at  this  stage  of  the  tanning  process  to 
so  compress  the  leather  as  to  close  its  pores,  therefore  it 
is  impracticable  to  overcome  the  irregularity  in  thickness 
by  making  the  leather  conform  to  the  rollers.  The 
latter  difficulty  obtains  with  all  other  hard  surfaced 
rollers,  even  though  the  discoloring  of  the  leather  from 
corrosion  might  not  be  experienced. 

Many  machines  have  been  devised  for  splitting  and 
rolling  leather  at  one  operation.  But  this  process  of 
Mr.  Whitney’s  is  especially  designed  for  the  use  of  the 
tanner ;  and  the  only  office  it  is  intended  to  perform  is 
that  of  expressing  the  tanning  liquor  or  water  from  the 
leather  in  order  to  prepare  it  for  the  action  of  such  ma¬ 
chines  as  have  been  devised  for  splitting  leather. 

A  A  is  a  frame  constructed  in  a  suitable  manner  to  re¬ 
ceive  the  component  parts  of  the  machine.  B  B  are 
two  rollers  of  equal  size,  placed  one  above  another,  and, 
with  their  journals  C  C,  revolving  in  boxes  D  D  and  E. 
The  revolution  of  the  rollers  is  effected  by  means  of 
gears  F,  G,  H,  I,  which  are  arranged  so  as  to  allow  the 
rollers  to  be  set  at  any  required  distance  apart  without 
breaking  the  gearing  connection  as  shown. 

A  gear  F  is  fixed  to  the  upper  roller,  and  a  corres- 


550  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

ponding  gear  to  the  lower  roller  outside  of  the  journals; 
these  gears  F  and  I  are  both  of  the  same  size,  and  then- 
diameter  being  less  than  the  diameter  of  the  rollers,  the 
teeth  of  one  never  come  in  contact  with  the  teeth  of  the 
other.  The  intermediate  gears  G  and  H  are  both  of  a 
size,  but  a  little  larger  than  the  roller  gears  F  and  I ; 
they  are  placed  back  of  the  roller  gears,  and  fitted  to 
revolve  on  studs  J,  J,  attached  to  the  frame.  The  lower 
intermediate  gear  H  meshes  into  and  drives  the  roller 
gear  I;  it  also  meshes  into  and  drives  the  upper  inter¬ 
mediate  gear  G,  and  the  upper  intermediate  gear  G 
meshes  into  and  drives  the  upper  roller  gear  E. 

Motion  is  given  to  the  rollers  through  the  gears  by  a 
driving  wheel  K,  with  a  pinion  L  attached  thereto, 
which  meshes  into  and  drives  the  lower  intermediate 
gear  Ft ;  the  pinion  L  is  made  fast  to  the  driving  wheel 
K,  and  is  fitted  to  revolve  on  a  stud  M,  set  in  the  frame 
below  the  lower  intermediate  gear  H.  The  roller  boxes, 
D  U  and  E  E,  have  a  tongue  at  each  end,  as  represented 
in  Figs.  165,  166,  167,  168,  and  are  made  to  slide  up 
and  down  in  grooves  N  N,  'formed  in  the  frame  A  A. 
At  each  end  of  the  upper  roller,  directly  over  the  jour¬ 
nals  C  C,  there  is  a  gear  screw  a,  hung  to  the  cap  piece 
O  of  the  frame,  and  made  to  revolve  in  holes  formed 
therein,  and  fitted  to  screw  in  the  upper  roller  box  D, 
for  the  purpose  of  elevating  or  depressing  the  upper 
roller.  These  screws  a,  a  stand  in  a  vertical  position, 
and  have  a  collar  above  and  below  the  cap  piece  O,  to 
prevent  them  from  sliding  up  or  down,  and  each  screw 
has  a  fixed  level  gear  b  on  the  upper  end  above  the  cap 
piece  O.  A  horizontal  shaft  c  is  placed  above  the  cap 
piece  O,  running  lengthways  of  the  machine,  and  fitted 
to  revolve  in  boxes  d  d  on  the  cap  piece  O,  with  a  fixed 
level  wheel  e  e  on  each,  and  corresponding  with  those 
of  the  screws,  and  fitted  to  mesh  therein.  On  one  end 
of  this  shaft  c,  outside  of  the  level  gear,  there  is  a  fixed 
hand-wheel  /,  by  which  the  shaft  may  be  turned  at 
pleasure.  A  rubber  spring  g,  or  its  equivalent,  is  con¬ 
fined  in  box  h ,  and  placed  directly  under  each  of  the 
lower  roller  boxes  E  E,  of  sufficient  power  to  give  the 


IMPROVED  MACHINE  FOR  ROLLING  LEATHER. 


551 


required  pressure.  Over  each  rubber  spring  g  there  is 
an  oil  protecting  cap  i,  on  which  the  roller  boxes  E  E 
rest.  This  cap  i  projects  clown  on  all  sides  outside  of 
the  box  n,  and  is  fitted  to  slide  freely  up  and  down 
thereon,  and  made  to  cover  the  spring  g ,  and  keep  the 
oil  used  in  lubricating  the  journals  from  coming  in  con¬ 
tact  with  it ;  the  cap  i  also  has  a  stirrup  j  attached  to 
it,  as  represented  in  Figs.  169  and  170.  There  are  two 
horizontal  levers,  A ,  k ,  one  at  each  end  of  the  machine, 
extending  longitudinally  directly  under  the  centre  of 
the  roller  B.  Each  of  these  levers  k  extend  through 
and  rest  on  the  stirrup  j,  and  are  hung  at  the  outer  end 
of  the  pins  1 1  for  their  fulcra  outside  of  the  frames. 
There  are  two  connecting  links  m,  m,  one  attached  to 
the  inner  end  of  each  lever  A,  by  a  pin  w,  and  extending 
downwards ;  both  of  them  are  connected  by  a  pin  o,  to 
a  horizontal  treadle  p,  running  transversely  through  the 
lower  part  of  the  machine  at  the  centre  of  its  length. 
The  treadle  p  is  hung  at  its  rear,  and  on  a  pin  g ,  in 
the  back  part  of  the  frame  and  the  forward,  and 
extends  out  beyond  the  front  of  the  frame,  so  as  to 
give  a  convenient  chance  to  place  the  foot  upon  it. 
Thus  it  will  be  readily  seen  that  by  giving  a  gentle 
downward  pressure  with  the  foot  on  the  treadle,  the 
combined  action  of  the  levers  A,  k,  on  the  stirrups  j,  j, 
will  cause  a  depression  of  the  oil  protecting  caps  *,  *, 
together  with  the  lower  roller  B. 

When  the  pressure  on  the  rollers  is  not  given  by  the 
use  of  springs,  this  combination  of  levers  may  be  applied 
to  give  the  pressure  by  extending  the  stirrups  up,  and 
attaching  them  to  the  upper  roller  boxes  D  D,  and  at¬ 
taching  the  geared  screws  a  a  to  the  lower  boxes  E  E  ; 
in  that  case  the  pressure  would  be  given  by  the  foot  on 
the  treadle.  This  combination  of  levers  may  also  be 
used  to  give  the  pressure  in  another  form,  as  represented 
in  Fig.  164  ;  the  only  change  necessary  to  be  made  is  to 
place  the  fulcra  pins  l,  l,  of  the  levers  A,  A,  inside  of  the 
frame  instead  of  outside,  and  stand  an  upright  rod  r, 
Fig.  164,  on  the  outer  end  of  each  lever  A,  extending  up 
centrally  to  the  under  side  of  the  lower  roller  boxes  E  E. 


552  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

Thus,  by  giving  a  gentle  downward  pressure  with  the 
foot  on  the  treadle  p,  the  combined  action  of  the 
levers  k  k  will  cause  an  upward  pressure  to  the  lower 
roller  B ;  in  this  case  the  geared  screws  would  be  at¬ 
tached  to  the  upper  roller  boxes,  as  shown  in  Figs.  161 
and  162. 

Operation, — Wet  leather  to  be  deprived  of  water  or 
tanning  liquor,  is  introduced  between  two  rollers  after 
the  same  have  been  adjusted  apart  to  the  upper  degree ; 
this  adjustment  being  effected  by  depressing  the  treadle 
or  raising  the  upper  roller  with  the  geared  screws.  The 
leather  having  been  introduced,  the  rollers  are  adjusted 
together  by  withdrawing  the  foot  from  the  treadle  and 
lowering  the  boxes  of  the  upper  roller  with  the  geared 
screws.  Now  by  operating  the  gearing,  the  rollers  B 
have  a  uniform  rotary  motion  imparted  to  them,  and 
the  leather  is  carried  through  under  a  pressure  due  to 
the  rubber  surfaces  and  to  the  geared  screws  and  to  the 
springs  g  g.  This  action  upon  the  leather  causes  a 
thorough  expression  of  the  water  or  tanning  liquor 
therefrom.  The  amount  of  the  pressure  is  graduated 
by  depressing  the  strings  g ,  g ,  and  operating  the  geared 
screws.  It  is  obvious  that  the  rubber  surfaces  of  the 
rollers  accommodate  themselves  to  the  irregular  surface 
of  the  leather,  and  thus  a  uniform  action  is  obtained. 
It  is  also  obvious  that  the  rubber  surfaces  protect  the 
leather  from  discoloration  as  the  tanning  liquor  cannot 
get  to  the  iron  of  the  rollers  so  as  to  cause  a  corrosion 
thereof.  It  is  also  obvious  that  the  pores  of  the  leather 
will  not  be  closed  by  hardening  or  flattening  down  the 
leather,  as  the  leather  is  between  elastic  surfaces. 


CHAPTER  CLXYI. 

MACHINES  FOR  FINISHING  LEATHER. 

S.  P.  Cobb,  of  South  Danvers,  Mass.,  patented,  in 
1860,  a  machine  for  finishing  leather,  of  which  the 
following  is  a  description. 

Fig.  171  is  a  side  elevation. 


MACHINES  FOR  FINISHING  LEATHER, 


553 


Fig-.  171. 


Fig.  172  is  a  front  elevation. 

Fig:.  173  is  a  transverse  and  central  section  of  the 
machine. 

Fig.  174,  rear  view  of  the  vibrator  and  parts  at  its 
foot. 

Fig.  175,  top  view  of  the  bed  cams,  their  connection 
and  operating  screws. 

In  the  drawings,  A  exhibits  a  table,  from  and  above 
which  a  frame  B  extends  and  serves  to  support  a  vibra¬ 
tor  or  vibratory  arm  D  and  a  fly-wheel  E.  This  arm 
supports  the  sleeker  or  finishing  tool  which  in  this 
machine  is  fastened  to  a  tilting  plate  or  frame  b,  which 
at  its  front  edge  is  hinged  to  what  is  termed  the  carrier 
o.  This  carrier  slides  freely  in  a  longitudinal  direction. 


554  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


Fi<r.  172. 


mgs! 


within  the  vibrator  I),  and  at  or  near  its  upper  end  is 
jointed  to  a  forked  connecting  rod  F,  which  straddles 
the  vibrator,  and  is  jointed  to  the  front  side  thereof,  as 
shown  at  d.  Each  joint  pin  e  of  the  carrier  c  projects 
through  a  slod  f  made  in  the  vibrator,  as  shown  in 
Figure  171  ;  the  near  end  of  the  connecting  rod  being 
applied  to,  and  so  as  to  turn  on  a  crank  pin  g  extending 
from  the  side  of  the  wheel.  By  revolving  the  wheel 
the  vibrator  with  the  carrier  and  finishing  tool  will  not 
only  have  an  oscillating  motion  imparted  to  them,  but 
the  carrier  c  will  be  raised  so  as  to  lift  thereon  during 
the  movement  of  the  vibrator  away  from  the  fly-wheel, 
the  tool  being  forced  down  upon  the  skin  during  the 
return  movement  of  the  vibrator. 


MACHINES  FOR  FINISHING  LEATHER 


555 


Fig.  173. 


Within  the  carrier  c  there  is  a  short  horizontal  shaft 
h ,  which  supports  a  sectoral  lever  i ;  this  lever  has  its 
tail  part  jointed  to  a  connecting  rod  k,  whose  lower 
hinder  part  hinges  to  the  tilting  plate  #or  frame  b. 
Furthermore,  the  toothed  section  of  the  lever  i  engages 
with  a  spring  click  l ,  carrying  the  angular  tooth  V,  and 
being  supported  by  the  carrier  c ,  the  whole  being  arranged 
as  shown  in  Figures  173,  174,  176,  the  latter  being  a 
transverse  and  vertical  section  of  the  vibrator  D  and  the 
carrier  c.  The  shaft  h  extends  through  a  slat  m  (made 
in  the  vibrator)  and  has  an  arm  or  lever  n  projecting 
from  it,  as  shown  in  drawing.  By  means  of  such  an 
arm  n,  shaft  h ,  sectoral  lever  i  and  click,  the  angular 
position  of  the  tool,  relatively  to  the  upper  surface  of 


556  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


the  bed,  may  be  varied  ;  it  being  difficult,  if  not  im¬ 
possible,  however,  to  accomplish  this,  when  the  vibrator 
is  in  rapid  motion.  It  has  been  applied  to  the  vibrator 
and  its  tilting  plate,  a  mechanism  by  which  the  tilting 
plate,  while  the  vibrator  may  be  in  oscillation,  may  be 
moved  in  its  fulcrum,  so  as  to  change  the  angle  of  the 


MACHINES  FOR  FINISHING  LEATHER. 


557 


tool  to  the  bed  while  the  tool  may  be  passing  over  any 
portion  of  a  skin.  As  a  skin  will  often  be  thicker  in 
some'parts  than  in  others,  it  becomes  desirable  to  have 
some  means  by  which  the  pressure  or  action  of  the  finish¬ 
ing  tool  may  be  equalized  on  the  surface,  and  this  while 
the  said  tool  may  be  in  movement. 

In  order  to  accomplish  this,  apply  to  the  vibrator  a 
slider  D  to  slide  thereon.  From  this  slider  three  pro¬ 
jections,  p,  q ,  r,  extend,  as  shown  in  Figs.  171,  172. 
The  lever  n ,  before  described,  extends  between  the  pro¬ 
jections  q ,  r,  while  the  other  projection  p  is  extended  into 
the  slot  S  of  a  long  lever  I,  whose  fulcrum  t  is  supported 
by  the  frame  B.  The  said  lever,  near  its  opposite  end, 
is  pressed  against  the  frame  by  a  friction-plate  u ,  held 
in  place  by  screws  v  v.  By  laying  hold  of  the  slatted 
lever,  and  forcing  it  either  downward  or  upward,  one  of 
the  pins  q  r  will  be  made  to  so  act  on  the  lever  or  arm 
n  as  to  move  the  same  and  steadily  change  the  angular 
position  of  the  tilting-plate  or  its  tool  relatively  to  the 
bed. 

Furthermore,  the  said  bed,  as  in  various  other  leather 
or  morocco-finishing  machines,  plays  vertically  within 
the  table  A,  and  rests  on  the  tops  of  two  cams,  K,  L, 
which,  in  their  turn,  are  respectively  supported  on  two 
other  cams  M  N.  These  latter  cams  are  upheld  by  two 
vertical  rods  O',  O',  each  cam  turning  freely  on  its  rod, 
but  being  supported  on  a  shoulder  X,  formed  on  the 
rod.  The  two  rods  play  vertically  with  a  frame  P, 
which  supports  springs  Y,  Y,  through  which  the  rods 
respectively  pass,  and  on  which  they  are  sustained  by 
means  of  screw-nuts  Z,  Z,  screwed  on  the  rods,  the  whole 
being  as  shown  in  the  drawings.  In  this  way  the  bed 
C  may  be  said  to  be  supported  on  springs. 

The  touching  surfaces  of  the  two  cams  K,  M,  or  L, 
N,  are  helical  in  form.  The  two  lower  cams  are  con¬ 
nected  on  the  same  side  each  by  a  rod  a\  whose  ends, 
by  means  of  joint-pins,  are  connected  to  projections  or 
flanches  b\  b\  of  the  lower  cams,  the  same  being  such  as 
to  enable  the  two  cams  to  move  or  turn  simultaneously 


558  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


in  the  same  direction,  while  the  rod  a',  may  be  moving 
lengthwise. 

The  other  two  cams  are  similarly  connected  by  a  rod 
o',  but  the  rod  extends  from  one  side  of  one  cam  to  the 
opposite  side  of  the  other.  Screw  rods  d',  d,  are  con¬ 
nected  with  the  two  rods  a' d  respectively,  and  screwed 
throughout  a  stationary  plate  f,  and  have  cranks  a'  h' 
on  their  outer  ends,  the  whole  being  so  that,  by  turning 
either  crank,  a  longitudinal  movement  shall  be  imparted 
to  the  rod  a'  or  d ,  with  which  the  screw-rod  of  the  crank 
may  be  directly  connected.  By  revolving  one  crank,  a 


Fig.  ITT. 


MACHINES  FOR  FINISHING  LEATHER. 


559 


vertical  movement  of  the  bed  will  be  produced.  By 
revolving  the  other,  the  bed  may  be  tipped  as  occasion 
may  require.  Thus,  by  means  of  the  mechanism  directly 
below  the  bed,  the  vertical  adjustment  of  opposite  ends 
of  the  bed  may  be  varied  so  as  to  either  raise  or  depress 
both  ends  equally  at  the  same  time,  or  unequally,  as  cir¬ 
cumstances  may  require. 

In  1863,  Mr.  S.  P.  Cobb  invented  and  patented  another 
machine  for  dicing,  polishing,  or  finishing  leather,  a  de¬ 
scription  of  which  will,  we  think,  interest  our  readers. 


560  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

Fig.  177  is  a  side  elevation  of  the  machine. 
Fig.#178  is  a  front  elevation  of  the  machine. 

Fig.  179  is  a  vertical  section  of  the  machine. 

Fig.  179. 


The  nature  of  his  invention  consists  as  follows : — 
First,  in  a  peculiar  mechanism  for  obtaining  the  com¬ 
pound  movement  of  the  vibrator  or  dicing  staff ;  also  in 
the  combination  and  arrangement  of  a  brush  or  cleansing 
mechanism,  with  the  dicer  or  finishing  tool  and  its  staff 
or  vibrator ;  also  in  the  combination  and  arrangement  of 
an  adjustable  smoothing  tool  with  its  dicer  and  its  staff ; 


MACHINES  FOR  FINISHING  LEATHER. 


561 


also  in  the  combination  and  arrangement  of  a  dicer 
cleansing  mechanism,  with  the  dicer,  its  staff,  and  curved 
bed. 

In  the  drawings,  A  exhibits  a  table  from  and  above 
which  a  frame  B  extends,  and  serves  to  support  the  ful¬ 
crum  S  of  a  rocker  lever  c,  which  is  arranged  as  shown 
in  the  figures.  The  dicing  staff  or  vibrator  D  is  jointed 
to  one  arm  of  the  said  rocker  lever,  and  at  its  lower  end 
supports  the  sleeker  dicer,  or  finishing  tool  «,  which  is 
fastened  to  a  tilting  plate  or  frame  5,  hinged  to  the  lower 
end  of  the  vibrator  or  dicing  staff  D.  A  forked  connect¬ 
ing  rod  straddles  the  vibrator,  is  jointed  to  it  and  to  the 
crank  pin  of  a  fly-wheel  E.  Furthermore  there  is  jointed 
to  the  connecting  rod  within  its  fork,  and  a  short  dis-  * 
tance  from  the  dicer  staff,  a  pitman  c,  which  extends  up¬ 
wards,  and  at  or  near  its  upper  end  is  jointed  to  the 
rocker  lever  c  hereinbefore  described,  the  arrangement 
of  the  said  pitman  with  respect  to  the  dicing  staff  and 
rocker  lever  being  as  shown  in  Figs.  177  and  179.  On 
revolving  the  fly-wheel  in  the  direction  of  the  arrow  ( y ) 
marked  thereon,  the  dicer  staff  will  not  only  be  vibrated 
with  a  pendulous  motion,  but  while  moving  towards  the 
fly-wheel,  the  said  dicing  staff  will  be  removed  or  pressed 
downwards  towards  the  bed,  in  a  manner  to  keep  the 
dicing  or  finishing  tool  in  contact  with  a  piece  of  leather 
when  on  the  bed.  So  while  moving  away  from  the  bed, 
the  dicing  staff  will  be  raised  upwards,  so  as  to  elevate 
the  dicer  or  polishing  tool  entirely  off  and  keep  it  out 
of  contact  with  the  leather. 

In  advance  of  the  polisher  or  dicing  tool,  there  is 
arranged  a  brush  H  held  by  a  suitable  supporting  frame 
d ,  having  one  or  more  springs  e  so  arranged  and  applied 
to  it  and  the  dicer  staff  as  to  press  the  brush  in  a  down¬ 
ward  direction  and  upon  the  leather,  while  such  leather 
may  be  resting  on  the  bed  G.  This  brush  moves  with 
the  dicer  and  its  staff,  and  is  for  the  purpose  of  removing 
from  the  surface  of  the  leather,  and  in  advance  of  the 
dicer,  any  dirt,  grit,  or  any  extraneous  matter  that  may 
collect  on  the  leather,  and  be  likely  to  cause  injury  to 
its  surface  from  the  action  of  the  dicer.  There  is  also 
36 


562  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

placed  to  the  rear  of  the  dicer*- a  smoothing  tool  T,  it 
being  carried  by  a  clamp  f,  attached  to  the  dicer  staff. 
A  spring  g  suitably  applied  to  the  smoothing  tool  serves 
to  depress  it,  as  occasion  may  require.  The  object  of 
the  smoothing  tool  is  to  remove  from  the  surface  of  the 
leather,  while  the  machine  may  be  at  work,  more  or 
less  of  the  graining  made  by  the  dicing  tool,  or,  in  other 
words,  to  low  down  the  graining  as  may  be  desirable. 
The  said  smoothing  tool  may  also  be  employed  irrespec¬ 
tive  of  the  dicing  tool,  and  either  one  or  both  may  be 
used  as  occasion  may  require  ;  a  rod  i,  jointed  to  the  tilt¬ 
ing  plate  b  of  the  dicing  tool,  extends  upwards  along 
the  dicer  staff,  the  said  rod  at  its  upper  end  being  jointed 
to  the  shorter  arm  of  a  lever  k ,  whose  fulcrum  t ,  is  sup¬ 
ported  by  the  dicer  staff.  This  lever  projects  from  the 
dicer  staff,  and  has  projecting  from  its  longer  arm  a 
pin  or  stud  which  goes  between  the  prongs  of  a  forked 
lever  m,  formed  and  arranged  as  shown  in  the  figures. 
By  laying  hold  of  the  longer  arm  of  sai'd  forked  lever, 
and  moving  the  same,  the  dicer  tilting  frame  may  be 
either  raised  or  lowered,  as  circumstances  may  require. 

At  the  front  end  of  the  curved  bed  G,  there  is 
arranged  a  dicer  cleaning  tool  or  scraper  0,  which  is 
supported  by  a  vibratory  lever  p ,  to  which  vibrating 
movements  may  be  imparted  by  means  of  a  foot  lever  q, 
and  a  connecting  rod  r.  The  same  being  arranged  as 
shown  in  Figs.  177  and  179.  By  elevating  the  scraper 
previous  to  the  expiration  of  any  advance  movement  of 
the  dicer,  the  said  dicer  in  the  continuation  of  its  move¬ 
ment  will  be  carried  in  contact  with  the  scraper  in  such 
manner  as  to  be  cleaned  or  scraped  thereby.  In  this 
way  the  gi'ease  or  dirt  which  may  collect  on  the  dicer 
or  polishing  tool  may  be  removed  therefrom. 

The  advantages  of  this  machine  are  the  following: — 

1st.  It  is  noiseless  comparatively,  and  adapted  to  all 
the  different  kinds  of  work  of  all  others  combined  with 
much  more  convenience. 

2d.  The  tools  are  carried  in  an  oblique  position, 
which  may  be  varied  so  as  to  make  a  sharp  or  flat  angle 
in  relation  to  the  bed,  which  is  done  by  the  rod  i,  i, 


LEATHER  POLISHING  MACHINE. 


563 


encased  in  the  pendulum  and  connected  at  or  near  b,  to 
the  tilting  plate  b ,  and  operated  by  the  long  armed 
forked  lever  m  m  acting  on  the  pin  of  the  short  lever  at 
I,  which  is  connected  with  the  encased  rod  i,  i,  etc.,  all 
done  while  the  machine  is  at  work. 

3d.  The  bed  may  be  adjusted  (by  means  of  the  cams 
and  rods)  by  the  workman  without  leaving  his  place  or 
stopping  his  work. 

4th.  The  tools  may  be  cleaned  from  dirt  or  any  ex¬ 
traneous  matters  which  may  chance  to  stick  to  them 
while  at  work,  without  stopping  the  machine  by  means 
of  a  scraper  at  the  back  end  of  the  bed  and  operated  by 
the  foot  rod  g  and  its  connection  at  the  front  end. 

Any  kind  of  tool  may  be  used,  either  stone,  glass,  or 
steel.  There  is  also  an  apparatus  for  pebbling,  which 
can  be  attached  at  pleasure ;  and  further,  a  brush  which 
can  be  used  in  connection  with  the  other  tools,  or  with¬ 
out,  and  is  nicely  adapted  to  belt,  cord  leather,  etc. 


CHAPTER  CLXVII. 

LEATHER  POLISHING  MACHINE. 

The  highly-finished  surface  of  fine  leather  is  usually 
imparted  by  hand  labor.  In  the  following  we  present 
a  view  of  the  machine  for  accomplishing  this  object, 
which  does  work  in  a  superior  manner,  and  effects  a 
great  saving  in  time  and  labor.  This  machine  was 
invented  by  Messrs.  R.  and  C.  Smith,  of  Stockport,  New 
York.  The  construction  and  operation  of  this  machine 
is  as  follows : — 

The  framing  A  carries  a  vertical  shaft  B,  which 
works  'between  two  parallel  bars  C  at  the  top,  and  is 
connected  at  D  to  a  bar  sliding  between  two  rollers  at 
E  and  F.  This  vertical  shaft  B  is  jointed  to  the  con¬ 
necting  rod  G ,  which,  in  turn,  is  fixed  to  a  cross-head 
sliding  on  guides  between  the  timbers  H;  from  this 
cross-head  proceeds  the  pitman  I  to  the  crank  wheel  J, 
which  is  turned  by  power  of  any  kind,  either  steam, 
water,  or  by  hand  when  neither  of  the  other  two  is 


564  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


Pig.  180. 


available  ;  the  bar  B  has  a  metallic  roller  K,  fastened 
at  its  lowest  extremity,  so  that  it  can  be  adjusted  to  suit 
the  nature  of  the  work,  and  the  skin  to  be  polished  rests 
upon  a  metallic  plate  underneath  it.  At  one  side  of  the 
skin  may  be  seen  a  clamp*  L ;  the  skin  is  attached  to 
this,  as  shown,  and  the  clamp  is  then  fed  over  the  surface 
of  the  table,  the  roller,  which  is  the  polisher,  acting  on 


perkins’s  machine  for  graining  leather.  565 


it  continually.  The  belt  which  drives  the  feed  gear  is 
seen  at  M.  There  is  also  an  arrangement  for  raising 
the  tool  stock  so  that  the  operator  can  place  another 
skin  underneath  the  roller  or  tool  when  the  first  one  is 
completed.  This  arrangement  consists  in  applying  a 
lever  at  one  side  of  the  frame  so  that  the  workman  can 
press  upon  it  with  his  foot,  and  then  accomplish  the 
object.  The  frame  slides  through  mortises  N  at  the 
bottom.  The  stroke  of  this  machine  may  be  altered  at 
will  by  simply  turning  the  hand  wheel  O.  This  wheel 
is  on  a  shaft  that  runs  through  the  main  driving  shaft, 
and  the  pinion  P  is  secured  to  it.  There  is  a  rack  Q,  on 
one  side  of  the  crank,  which  elevates  or  depresses  the 
pin  when  the  pinion  is  turned ;  suitable  means  are  pro¬ 
vided  for  keeping  the  pin  stationary,  except  when  it  is 
necessary  to  move  it.  These  are  the  principal  parts. 
It  is  obvious  that  when  the  tool  stock  B  is  put  in  motion 
that  the  sliding  action  of  the  wheel  K  will  impart  a  high 
finish  to  the  leather  in  a  manner  apparent  to  every  one 
without  any  further  explanations.  These  machines  are 
said  to  work  exceedingly  well.  Several  of  them  have 
already  been  put  in  operation. 


CHAPTER  CLXVIXI. 

JACOB  PERKINS’S  MACHINE  FOR  POMMELING  AND 
GRAINING  LEATHFR. 

Fig.  181,  side  view. 

Fig.  182,  front  view. 

Fig.  183,  plan. 

a.  Framework  held  together  by  bolts  with  nuts. 

b.  Farge  horizontal  wooden  shaft,  its  iron  pivot  c  turn¬ 
ing  in  the  copper  collars  d. 

e.  Four  wooden  arms  radiating  from  the  middle  of 
the  shaft  b,  and  curved  at  their  bases. 

f  Four  fluted  or  grooved  cylinders  of  lignum  vitae 
wood,  in  the  ends  of  the  wooden  arms.  The  grooves 
are  near  or  far  from  each  other,  according  to  the  grain 
intended  to  be  given  to  the  leather. 


566  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


Fig.  181. 


g.  Two  iron  grooves  attached  to  each  of  the  arms,  and 
receiving  the  pivots  of  fhe  cylinders  f  in  their  extremi¬ 
ties  ;  these  grooves  are  kept  in  place  by  the  guides  i,  and 
slide  against  the  blocks  h ,  Fig.  181. 

k.  Fig.  181.  Springs  resting  against  the  lower  part 


perkins’s  machine  for  graining  leather.  567 


Fig.  183. 


of  the  base  of  the  grooves  g,  and  by  their  elasticity  tend¬ 
ing  to  push  these  grooves  away  from  the  shaft  b. 

l.  Screw  and  nut,  the  end  of  which  presses  to  the 
required  extent  upon  the  lower  end  of  the  groove  g. 
When  this  screw  is  tightened,  the  groove  presses  down 
the  spring,  and  approaches  the  shaft ;  when  loosened  the 
opposite  movement  takes  place. 

m.  Pieces  forming  a  support  or  frame,  and  curved  in 
the  form  of  arcs  of  the  circle  of  which  the  shaft  is  the 
centre,  so  as  to  allow  the  arms  to  revolve  freely.  This 
frame  should  be  very  firm,  and  supplied  with  a  surface 
of  hard  wood  for  the  cylinders  to  rotate  upon. 

n.  Circle  attached  by  bolts  to  the  arms,  and  serving 
to  strengthen  them. 

o.  Pulley  upon  the  shaft  6,  intended  to  receive  the 
motive  power  by  means  of  a  band. 

The  leather,  when  prepared  in  the  ordinary  way,  and 
ready  to  be  grained  and  polished,  is  placed  upon  the 
wooden  table  or  frame  m,  and  the  shaft  b  is  turned. 
The  grooved  cylinders  f  stamp  furrowed  surfaces  upon 
the  leather,  and  owing  to  the  resiliency  of  the  springs, 


56 8  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

adapt  themselves  to  its  variations  of  surface  and  thick¬ 
ness.  The  skin  is  moved  about  by  the  workman  so  that 
the  different  portions  shall  all  be  grained  in  the  required 
directions,  and  during  the  process,  the  surface  of  hard 
wood  m  is  from  time  to  time  moistened  with  water  or  oil, 
to  prevent  it  from  becoming  heated. 

The  cylinders  f  in  the  course  of  their  revolution,  press 
against  brushes  which  keep  them  clean.  Upon  each  of 
their  axles  is  a  ratchet-wheel  with  a  catch  p,  Fig.  181, 
the  object  of  which  is  to  prevent  them  from  revolving. 
When  the  grooves  of  the  cylinder  are  worn  out  at  one 
point,  they  can  be  renewed  by  turning  the  cylinder 
r^und,  so  as  to  present  a  new  part  of  its  circumference. 

The  shaft,  the  pulleys,  the  arms,  and  the  circular  sup¬ 
port  can  all  be  made  of  cast-iron  in  one  piece. 


CHAPTER  CLXIX. 

NISBET’S  GROUNDING  AND  PUMICING  MACHINE. 

Mr.  John  Nisbet,  of  England,  recommends  the  substi¬ 
tution  of  machinery  for  the  hand  in  the  laborious  pro¬ 
cess  of  grounding,  or  frizing,  and  has  invented  for  that 
purpose  a  very  ingeniously  constructed  apparatus.  He 
employs  knives  and  pumice  stones,  or  other  sufficiently 
rough  materials,  set  into  revolving  cylinders  which  are 
made  to  turn  in  contact  with  the  surfaces  of  leather. 
Fig.  184  represents  a  side  view ;  and  Fig.  185  a  longitu¬ 
dinal  section  of  one  of  these  machines;  a  a,  framework, 


Fig.  184.  Fig.  185. 


b ,  axle  turning  in  the  supports  c  c,  and  made  to  revolve 
by  means  of  a  strap  around  the  pulley  d ;  e  e,  series  of 


nisbet’s  grounding  and  pumicing  machine.  569 

cross-pieces,  or  arms,  each  of  which  is  provided  with  a 
paring  knife/,  which,  by  the  revolution  of  the  shaft,  is 
brought  in  contact  with  and  made  to  pare  the  surface  of 
the  skin  or  portion  of  skin  placed  on  the  mattress  g. 
This  mattress  is  stuffed  with  hay  or  other  suitable 
material,  and  is  covered  with  oiled  leather.  It  is  placed 
upon  the  top  or  table  of  a  car  mounted  on  four  grooved 
wheels  h  h,  which  run  on  the  railroad  i  i. 

The  arms  which  carry  the  knives  are  made  to  revolve 
at  least  560  times  in  a  minute,  and  the  rapidity  of  mo¬ 
tion  can  be  increased  if  it  is  desirable  to  do  so. 

The  workman  places  the  skin,  or  portion  of  skin,  upon 
the  mattress,  and  pushes  the  car  forwards,  so  that  the 
end  of  the  piece  shall  be  under  one  of  the  series  of  blades. 
These  latter,  by  their  revolution,  then  draw  the  leather 
away  from  the  workman,  and  pare  its  surface  while  he 
retains  the  extremity  in  his  hands  and  retards  its  pro¬ 
gress  more  or  less  according  to  the  amount  of  action  to 
which  it  is  desired  to  expose  it.  When  one  side  is  thus 
pared  throughout,  the  band  is  slipped  off  from  the  pul¬ 
ley,  so  as  to  stop  the  revolution  of. the  axle;  the  car  is 
drawn  back,  the  leather  turned,  and  the  strap  being  re¬ 
placed,  the  other  side  is  made  to  undergo  the  same  treat¬ 
ment.  Besides  great  rapidity,  this  operation  secures  a 
uniform  paring  of  the  leather. 

When  light  and  thin  skins  are  treated  in  this  manner, 


Fig.  186. 


the  intervals  between  the  knives  are  filled  up  with 
wooden  blocks,  or  wedges,  so  that  the  axle  is  surrounded 


570  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


by  a  compact  cylinder  of  wood,  beyond  which  the  knives 
project  only  to  a  slight  extent.  Fig.  186  shows  the 
plan,  and  Fig.  187  the  side  view  of  the  machine  so  modi- 


Fig.  187. 


Js  * 


tied;  and  Figs.  188,  189,  190,  and  191,  exhibit  a  front 
view  of  the  arms  and  knives  from  between  which  the 


Fig.  188.  Fig.  189.  Fig.  190.  Fig.  191. 


fp 

b 

c9 

wooden’  wedges  have  been  removed  ;  a  section  ;  a  side 
view ;  and  front  view  of  the  series  of  knives  f,  and  of 
the  wedges  j. 

Figs.  186  and  187  also  represent  the  apparatus  for 
pumicing  leather.  The  pumice  stones  k,  or  other  suita¬ 
ble  rough  substances,  are  attached  to  the  shafts  m,  which 
are  made  to  revolve  by  the  ordinary  means.  In  other 
respects,  the  machine  resembles  the  preceding  one,  the 
same  letters  indicating  corresponding  parts  of  both. 

.  The  leather  submitted  to  the  action  of  this  machine, 
is  first  pared  by  means  of  two  sets  of  knives  f,  which 
are  represented  in  the  figure  as  turning  upon  two  shafts, 
and  it  then  passes  under  the  pumicing  cylinders,  which 

Fig.  192.  Fig.  193.  Fig.  194. 


act  progressively  upon  every  part  of  the  surface.  Figs. 
192  193,  and  194  exhibit,  the  first  a  section,  the  second 
a  side  view,  and  the  third  a  front  view  of  these  cylin- 


EMBOSSING  OF  LEATHER. 


571 


Fig.  195. 


ders  and  stones.  Figures  195  and  196  show,  the  one  a 
cross  section,  and  the  other  a  longitudinal  section  of  the 
pumicing  machine  while  in  action. 


CHAPTER  CLXX. 

EMBOSSING  OF  LEATHER. 

This  is  a  method  of  manufacturing  ornamental  leather 
intended  for  furniture,  hangings,  bookbinding,  and  other 
uses. 

Bernheim  and  Labouriaii’s  Process. — The  plates,  by 
means  of  which  the  figures  in  relief  are  stamped  upon 
the  leather,  in  this  process,  are  made  of  type-metal,  or 
fusible  alloy,  cast  in  plaster  moulds,  on  which  the  re¬ 
verse  of  the  figures  has  been  designed.  The  type-metal 
plates  are  used  for  stamping  leather  without  the  assist¬ 
ance  of  a  press,  by  which  they  would  be  broken  to 
pieces,  and  those  of  fusible  alloy  are  employed  for  large 
single  designs  in  panel  upon  hangings,  or  for  the  repe¬ 
tition  of  the  same  figures,  by  associating  a  number  of 
plates  together.  For  this  latter  purpose,  as  many  plates 
as  are  necessary  for  the  whole  design  are  placed  together 
upon  a  level  surface,  in  their  proper  places,  and  their 
edges  are  then  joined  together,  first  by  running  a  hot 
iron  along  them,  and  then  by  filling  up  the  interstices 


572  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

with  melted  fusible  metal.  The  projecting  veins  of  metal 
are  then  cut  and  scraped  off,  and  the  whole  presents 
the  appearance  of  a  single  plate. 

The  large  plates  thus  prepared  will  not  bear  the  force 
of  a  press,  but  are  used  with  the  assistance  of  heat.  The 
ingredients  of  which  the  alloy  is  composed  are  not  in 
the  proportion  to  make  the  most  fusible  metal,  the  quan¬ 
tity  of  lead  being  somewhat  greater  than  in  the  ordinary 
alloy.  Those  plates  which  are  intended  to  be  subjected 
to  the  action  of  the  press,  also,  have  a  smaller  quantity 
of  tin  in  their  composition  than  is  usual,  so  as  not  to  be 
rendered  brittle  by  an  excess  of  it.  These  latter  should 
be  perfectly  smooth  below,  and  should  be  of  considerable 
thickness.  They  are  prepared  of  the  proper  thickness 
in  the  following  manner:  A  fine  thin  sheet  of  tin-foil  is 
first  pressed  into  all  the  cavities  of  the  original  plaster 
mould,  so  as  to  give  a  reversed  copy  of  it,  and  a  plate  of 
softened  wax  of  the  desired  thickness  of  the  metal  plate, 
is  forced  into  it  so  as  to  take  its  form.  A  plaster  mould 
is  then  taken  of  this  wax  impression,  covered  with  tin- 
foil,  and  the  model  and  the  mould,  placed  parallel  to 
each  other,  are  separated  by  little  leaden  tubes,  which 
are  equal  in  height  to  the  thickness  of  the  wax-plate 
used  before. 

In  order  that  the  casting  should  be  successful,  the 
plaster  models  and  moulds  must  be  perfectly  dry,  and 
heated  to  the  temperature  of  the  fused  alloy,  and  when 
filled  must  be  placed  in  a  position  to  cool  rapidly. 

The  large  compound  plates  are  exposed,  in  stamping, 
to  the  action  of  heat  by  means  of  pipes  conveying  steam, 
placed  below  them. 

Two  means  of  stamping  leather  with  figures  in  relief 
are  resorted  to,  that  by  use  of  the  press,  and  that  in 
which  the.  stamping  is  effected  by  hand  or  the  chisel, 
with  the  assistance  of  heat.  The  leather  is  first  fulled 
in  tepid  water,  until  it  becomes  as  soft  as  it  is  possible 
to  make  it.  In  this  condition  it  is  placed  upon  the 
plate  without  being  stretched,  and  is  made  to  enter 
all  the  depressions  of  the  figures  by  pressing  and  squeez¬ 
ing  it  in  every  direction  with  the  fingers,  while  the  pro- 


BERNHEIM  AND  LABOURIAU’S  PROCESS. 


573 


jections  and  folds  upon  the  edges  of  the  design  are 
smoothed  down  by  a  wooden  instrument  like  the  chisel 
used  by  sculptors.  When  the  leather  is  in  contact  with 
all  parts  of  the  mould  or  plate,  if  the  character  of  the 
figures  is  such  as  to  admit  of  perpendicular  pressure,  the 
frame  is  filled  up  with  warm  sawdust,  and  the  gentle 
force  of  a  press  is  applied  above,  so  as  to  keep  the  leather 
and  metal  surfaces  in  contact.  After  a  time,  the  screw 
is  loosened,  the  moistened  sawdust  is  removed,  and  re¬ 
placed  with  fresh,  the  press  is  again  brought  to  bear,  and 
this  process  is  repeated  once  more.  At  the  end  of  the 
third  operation,  the  leather  will  generally  have  acquired 
enough  consistency  to  retain  the  form  impressed  upon 
it,  and  it  may  then  be  removed  from  the  plate  and  dried 
in  the  stove-room. 

If  the  plate  be  too  large  for  the  press,  or  if  there  are 
many  projections  on  its  surface,  having  slight  or  narrow 
bases,  the  pressure  must  be  conducted  entirely  by  hand. 
For  this  purpose  the  plate  is  warmed  by  placing  it  upon 
the  tubes  conveying  hot  air  or  steam,  and  the  moistened 
leather  is  laid  upon  it,  and  forced  down  into  all  the 
depressions  and  grooves  of  the  plate  by  means  of  paper- 
hangers’  paste,  which  is  thrust  and  pressed  down  into 
them  with  the  end  of  the  wooden  instrument  or  chisel, 
and  when  the  chief  cavities  are  filled  in  this  way,  the 
rest  of  the  surface  is  worked  so  as  to  bring  the  leather 
in  contact  with  the  plate  in  every  part.  The  folds 
which  form  at  the  borders  and  corners  are  then  smoothed 
out  with  the  chisel,  first  longitudinally,  and  then  across, 
until  they  are  made  to  disappear.  The  whole  surface 
of  the  leather  is  then  rubbed  with  a  dry  sponge  so  as  to 
remove  the  excess  of  moisture,  and  the  workman  then 
continues  forcing  it  down  into  the  depressions  with  a 
chisel,  until  it  is  perfectly  dry,  when  the  rest  of  the 
paste  is  removed  from  the  hollows.  The  elasticity  of 
the  leather,  when  dry,  allows  of  its  removal  from  the 
plates  even  when  the  elevations  on  the  latter  are  larger 
at  top  than  at  bottom. 

If  it  is  intended  to  stamp  a  design,  or  series  of 
designs,  the  dimensions  of  which  require  the  use  of  a 


574  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

number  of  skins,  the  latter  are  first  cut  into  parallelo¬ 
grams,  and  their  edges  are  pared  and  thinned  down. 
One  of  them  in  the  softened  state  is  then  placed  at  an 
angle  or  edge  of  the  plate,  and  is  impressed  with  the 
figures  in  the  manner  before  described.  A  second  skin 
is  then  placed  alongside  of  the  first,  with  one  edge  pro¬ 
jecting  about  an  inch  over  its  border,  and  is  printed  in 
the  same  way ;  a  third  is  placed  next  to  and  partly  over 
the  second,  and  so  on,  even  if  a  number  of  rows  of  skins 
are  required,  until  the  whole  extent  of  the  plate  is  oc¬ 
cupied.  After  the  skins  have  all  been  pressed,  sponged, 
worked  with  the  chisel,  and  dried,  their  overlying  edges 
are  gently  raised,  covered  with  strong  glue,  carefully 
replaced,  and  retained  in  their  original  position,  by 
covering  the  whole  with  sawdust  and  weighted  planks, 
until  it  dries  and  forms  a  continuous  sheet. 

By  these  two  processes,  leather  beautifully  ornamented 
in  relief,  and  suitable  for  many  purposes  of  luxury, 
ma*y  be  manufactured.  These  ornaments  may  be  allowed 
to  retain,  in  a  slight  degree,  the  suppleness  and  elasticity 
of  the  leather,  or  may  be  rendered  perfectly  firm  and 
hard,  by  pouring  into  them,  while  still  warm  upon  the 
castings,  a  solution  of  gum-lac  in  alcohol,  or  a  watery 
solution  of  glue,  and  filling  up  all  the  depressions  with 
paste,  sawdust,  or,  what  is  still  better,  the  raspings  of 
cork  mixed  with  glue.  Their  surfaces  may  be  made 
impervious  to  moisture,  by  the  penetration  of  the  gum- 
lac  or  of  other  resinous  material,  and  may  be  painted, 
gilded,  and  varnished. 

F.  W.  East's  Proem.— This  invention,  patented  in 
1851,  differs  from  the  usual  method  in  being  exclusively 
applicable  to  the  flesh  side  of  leather,  and  thus  pro¬ 
ducing  an  effect  superior  to  that  obtained  by  embossing 
the  grain  side.  It  is  adapted  to  all  tanned  skins  except 
those  which  are  oil-tanned. 

The  skins,  just  sufficiently  shaved  to  remove  flaws 
and  give  them  uniform  thickness,  are  to  be  immersed  in 
water  of  120°  F.,  and  brushed  on  the  flesh  side  to  re¬ 
move  dirt  and  open  the  fibre.  They  are  then  to  be 
folded  grain  side  inwards  and  the  edges  sewed  together 


degrand’s  machine. 


575 


in  bag  form,  so  as  to  prevent  the  intrusion  of  the  dye. 
The  dyeing  succeeds  “  scouring,”  and  “  sweetening,” 
and  is  effected  with  much  weaker  liquors  than  are  used 
for  dyeing  the  grain  side  of  skins ;  but  requires  a  longer 
time,  as  the  process  must  be  several  times  repeated  in 
order  that  the  color  may  penetrate  the  fibres,  and  appear 
uniform.  They  are  then  rinsed,  opened,  and  dried. 

When  dry,  they  are  to  be  “  perched”  on  the  flesh  side 
with  a  moderately  sharp  knife,  so  as  to  soften  the  fibres, 
and  nap  the  surface  without  cutting  the  flesh  off.  Each 
skin  is  to  be  again  folded  as  before,  and  passed  through 
a  glutinous  solution  of  one  part,  by  measure,  of  size  in 
three  parts  of  water ;  then  stretched  on  boards  to  dry, 
trimmed  around  the  edges,  and  bruised  on  the  surfaces 
with  cork,  to  render  them  soft,  the  flesh  side  being  kept 
outwards. 

The  skins,  just  previous  to  being  embossed,  are  moist¬ 
ened  on  the  grain  sides  with  clean  water,  and  then  laid 
together,  with  the  grain  sides  in  contact,  and  under 
cover  in  order  to  prevent  access  of  air,  and  thus  to  pro¬ 
mote  the  thorough  penetration  of  the  water  through 
the  hide,  thereby  making  the  gelatinous  matter  aux¬ 
iliary  to  the  production  of  a  gloss  upon  the  embossed 
parts.  The  embossing  is  done  with  engraved  rollers, 
previously  heated  to  250°,  and  exactly  in  the  same 
manner  as  is  employed  for  embossing  velvet,  cloth,  &c. 


CHAPTER  CLXXI. 

DEGRAND’S  MACHINE  FOR  SPLITTING  AND  SHAVING 

LEATHER. 

A  transverse  section  of  Degrand’s  machine  is  shown 
in  Fig.  197.  A  horizontal  knife  a,  longer  than  the 
greatest  width  of  a  skin,  is  fixed  upon  a  wooden  table 
b.  A  cast-iron  plate  b  is  set  in  the  table  in  front  of  the 
knife-blade,  and  is  intended  to  support  the  leather  c  at 
the  desired  elevation,  its  position  being  regulated  by 
screws  and  nuts.  It  is  movable  in  every  direction, 
being  supported  upon  four  springs.  Above  it,  a  little 


576  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


Fig.  197. 


wooden  shelf  d,  which  is  pressed  upon  by  a  roller  e, 
maintains* the  leather  in  close  contact  with  the  plate,  so 
as  to  flatten  and  stretch  it  thoroughly  before  it  is  exposed 
to  the  blade.  One  of  the  separated  surfaces  of  the  lea¬ 
ther,  as  it  rises  over  the  knife,  is  attached  to  a  wedge- 
shaped  tongue,  which  projects  from  the  whole  length  of 
the  wooden  roller  c,  and  is  wound  up  upon  the  latter  as 
it  advances. 

The  leather  is  seen  in  the  figure  as  split  by  the  blade 
of  the  knife,  the  upper  portion  of  it  being  already  rolled 
upon  the  cylinder  c.  The  lower  half  passes  down  under 
the  knife  through  a  slit  in  the  table,  and  the  uncut  por¬ 
tion,  which  is  about  to  be  exposed  to  the  action  of  the 
blade,  is  seen  resting  upon  the  table,  and  pressed  down 
by  the  upper  plate  d.  The  movement  of  revolution  is 
given  to  the  cylinder  by  a  winch  which  turns  a  pinion 
gearing  with  a  toothed  wheel  at  one  of  its  ends.  Two 
operations  are  required  to  split  the  leather,  one-half  of 
it  being  first  separated,  the  skin  being  then  unrolled  from 
the  cylinder,  turned,  and  the  split  part  attached  to  it,  so 
that  the  other  half  may  be  in  like  manner  divided.* 


*  The  author  has  omitted  to  explain  the  mode  of  forcing  the  edge 
of  the  leather  upon  the  knife-blade,  by  which  the  first  part  of  the  in¬ 
cision  is  effected.  The  process  can  only  be  rationally  understood  by 
supposing  that  a  longitudinal  incision  is  first  made  down  the  centre 
of  the  skin  extending  half  through  in  thickness,  and  that,  while  one 
edge  of  the  skin  is  attached  to  the  roller,  the  knife  is  accurately  en¬ 
gaged  in  the  bottom  of  the  cut  previously  made. 


GIRAUDON  S  MACHINE, 


577 


CHAPTER  CLXXII. 

GIRAUDON’S  MACHINE  FOR  SPLITTING  AND  SHAVING 

LEATHER. 

This  interesting  invention  has  been  described  by  M. 
Armengaud,  in  the  Publication  Industrielle  des  Machines , 
outils  et  appareils ,  t.  vi.  liv.  9.  The  machine  is  simple 


Fig.  198. 


578  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

in  construction,  operating  rapidly  and  continuously  upon 
the  skins  exposed  to  its  action,  and  can  be  employed 
either  for  the  purpose  of  dividing  the  leather  into  thin 
sheets  or  leaves,  or  for  that  of  diminishing  and  equaliz¬ 
ing  its  thickness. 

Fig.  200. 


Tig.  201. 


The  hide  or  skin  which  is  to  be  cut  is  placed  upon  the 
circumference  of  a  large  drum  or  cylinder  A  (Figs.  198, 


giraudon’s  machine. 


579 


199,  and  200),  carefully  turned  and  attached  to  three 
crosspieces  with  six  branches  or  spokes  b,  which  are  con¬ 
nected  with  the  cast-iron  horizontal  shaft  c.  This  cylin¬ 
der  is  hollowed  out,  as  seen  in  the  section  shown  in  Fig. 
201,  for  the  reception  of  a  kind  of  pincers  d  (Fig.  207), 
which  serve  to  support?  the  extremity  of  one  of  the  de¬ 
tached  portions  of  skin  against  the  edge  of  the  cylinder. 
For  this  purpose,  these  pincers  are  all  mounted  upon 
the  same  iron  axle  a ,  which  rests  upon  small  supports  5, 
fastened  to  the  cylinder,  and  they  are  kept  in  place  by 
a  flat,  angular  regulator. 

The  horizontal  shaft  c,  which  extends  on  each  side 
beyond  the  cast  framework  e,  carries  at  one  end  the 

Fig.  202.  Fig.  203. 


J' 


larger  cog-wheel  f,  which  is  geared  with  the  endless 
screw  e  (Figs.  202  and  203),  situated  at  the  lower  part 


Fig.  204.  Fig.  205. 


of  the  machine,  and  revolving  upon  the 
axle  f,  the  slow  movement  of  which  is 
produced  by  means  of  the  wheel  G,  the 
endless  chain  g,  and  the  pinion  h.  This 
pinion  turns  upon  the  cast-iron  shaft  h, 
which  is  made  to  revolve  by  means  of  a 
strap  passed  over  one  of  the  pulleys  i ;  a 


Fig.  207. 


580  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

fly-wheel  j  giving  the  necessary  uniformity  to  the  mo¬ 
tion.  A  roller  i,  at  the  end  of  a  counterpoised  lever  /, 
presses  against  the  endless  chain,  and  gives  it  the  proper 
amount  of  tension. 

The  shaft  h  is  elbowed  in  the  middle,  so  as  to  form  a 
crank  for  the  head  of  the  cast-iron  rod  k,  which  is 
articulated  at  its  other  end  with  the  middle  of  the  mov¬ 
able  rabbit  or  carriage  l  (Figs.  201  and  204).  At  the 
base  of  this  is  attached  the  long  cutting  steel  blade  which 
is  inclined  a  little  in  direction  to  the  horizon,  and  touches 
the  exterior  of  the  cylinder  when  made  to  approach  it. 
It  is  very  thin  and  of  an  undulating  form,  as  shown  in 
the  plan  (Fig.  205),  so  as  to  act  upon  the  leather  like  a 
saw,  the  teeth  of  which  are  rounded  off;  by  which 
arrangement  it  cuts  more  easily  and  with  less  wear  of 
edge.  This  knife-blade  is  attached  to  the  base  of  the 
.  rabbit  by  means  of  an  iron  plate  m,  the  position  of  which 
can  be  accurately  adjusted  with  a  screw. 

The  movable  rabbit  or  carriage  is  dove-tailed  into 
the  tops  of  two  cast-iron  supports  e,  which  compose  the 
framework.  The  grooved  plates  n  above  it  prevent  any 
deviation  from  the  reciprocating  rectilinear  movement 
produced  by  its  connection  with  the  crank.  Thus  the 
same  shaft  H  which  moves  the  crank  causes  the  revolu¬ 
tion  of  the  lower  axle  f  and  of  the  endless  screw,  by 
means  of  which  the  drum  upon  which  the  skin  is  wound 
is  also  turned  ;  but  with  a  motion  exceedingly  slow,  when 
compared  with  that  of  the  crank  above,  and  the  knife 
connected  with  it.  The  ratio  of  size  between  the  pinion 
It  and  the  wheel  G  being  as  one  to  eight,  and  the  large 
wheel  f  having  244  teeth,  it  follows  that  the  cylinder 
only  turns  once  while  the  axle  /'and  the  endless  screw 
are  making  244  revolutions,  and  the  main  shaft  h  is 
making  1952.  By  causing  the  main  shaft  to  revolve  75 
times  in  a  minute,  the  knife  is  made  to  cut  the  leather 
150  times,  so  that  a  skin  78.74  inches  in  length  will  be 
split  in  15 \  minutes. 

The  leather  is  maintained  in  close  contact  with  the 
cylinder  in  front  of  the  knife-blade  by  the  pressure  of  a 
series  of  flexible  spring-keys  which  adapt  themselves  to 


giraudon’s  machine. 


581 


its  irregularities  of  surface,  and  keep  its  uncut  edge 
firmly  pressed  down  by  means  of  a  crosspiece  extending 
along  its  whole  breadth  and  supported  by  projections 
upon  the  inside  of  the  framework.  A  strong  bar  g 
serves  to  support  the  other  ends  of  the  springs,  and  also 
assists  in  keeping  the  leather  applied  to  the  surface  of 
the  cylinder.  Two  grooved  uprights  y  are  adjusted  in 
rectangular  vertical  mortises  of  the  framework,  and  the 
screws  oc,  in  their  lower  parts,  regulate  the  height  of  the 
bar. 

The  lower  separated  portion  of  the  split  leather  re¬ 
mains  in  contact  with  the  cylinder  while  it  revolves, 
and  the  upper  part  may  be  rolled  otf,  if  desired,  upon  a 
roller  placed  above  the  machine. 

When  a  skin  is  divided  throughout,  in  order  to  replace 
it  by  a  fresh  one,  it  is  necessary  to  lower  the  cylinder 
from  its  position,  in  order  to  disengage  the  knife  from 
the  surfaces.  For  this  purpose,  the  cushions  r  of  its 
axle  are  adjusted  in  movable  collars  supported  upon 
uprights  s  and  s',  which  can  be  elevated  or  lowered  by 
means  of  iron  swipes  t,  which  are  supported  upon  the 
base  of  the  framework  e,  and  are  connected  by  a  cross¬ 
bar,  or  treadle,  which  the  workman  can  lower  by  a  pres¬ 
sure  of  his  foot,  the  collars  and  uprights  being  only  mov¬ 
able  in  a  vertical  direction.  In  order  that  the  cog-wheel 
and  the  screw  may  continue  in  gear  during  this  change 
of  position,  the  cushions  which  support  the  axle  of  the 
latter  are  connected  with  the  crossbar  between  the  two 
uprights. 

The  revolution  of  the  cylinder  can  be  stopped  at  plea¬ 
sure  by  ungearing  the  wheel  e,  which  can  be  moved 
upon  its  axle  by  the  handle  u  and  fork  v. 

Thirty-six  raw  hides  can  be  readily  divided  by  this 
machine  in  a  day  of  twelve  hours. 


582  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 


CHAPTER  CLXXIII. 

MACHINES  FOR  SPLITTING  AND  SHAVING  LEATHER. 

Richardson’s  Machine,  invented  by  Alpha  Richard¬ 
son,  of  Massachusetts,  is  generally  used  throughout  the 
United  States.  It  serves  for  splitting  either  green  or 
tanned  hides.  There  are  two  modifications,  that  shown 
in  perspective,  by  Fig.  208,  is  intended  for  splitting 


Fig.  208. 


upper  leather,  which  is  drawn  between  the  knife  and 
roller  by  means  of  a  crank  and  windlass.  This  is  styled 
the  Tanner  and  Currier’s  Machine.  A  is  the  cast-iron 
piece. connected  with  the  gauge-roller  B,  which  revolves 
on  the  centres  e  e,  and  is  turned  up  by  the  lever  o,  To 
allow  the  placing  of  the  leather  upon  the  top  of  the  knife 
and  back-spring  A  A.  The  skin  being  in  right  position, 
the  gauge  is  then  turned  back,  and  forms  the  gauge  for 
the  thickness  of  the  skins  which  may  be  regulated  at 
will,  by  means  of  the  screws  h  h.  B  is  the  roller  with 
the  sectional  tubes  g  g  g,  which  are  arranged  to  turn  on 
its  end,  and  to  serve  as  friction-rollers  when  the  shanks 
and  loose  part  of  the  skin  are  being  drawn  through. 
The  knife  D  is  bolted,  firmly,  to  the  bed  by  the  screws 
i  i  i  i.  The  leather  is  placed  upon  the  cylinder  C,  and 
drawn  through  against  the  knife  B  by  the  aid  of  the 
crank  at  the  end  of  the  machine. 


SPLITTING  AND  SHAVING  MACHINES. 


583 


The  leather  is  prepared  for  splitting  by  being  only 
partially  dried.  In  New  England  and  in  the  middle 
States  it  is  generally  split  before  it  is  wholly  tanned,  as 
the  quality  of  the  leather  i§  thought  to  be  improved  by 
finishing  the  tanning  after  it  has  been  thinned  or  divided 
by  the  machine. 

The  other  modification  of  the  machine  is  constructed 
for  splitting  and  skinning  sole  leather,  welt  leather,  and 
stiffenings  for  boot  and  shoemaker’s  use.  It  is  repre¬ 
sented  by  Fig.  209,  and  works  by  means  of  rollers  which 


Fig.  209. 


force  the  leather  against  the  edge  of  the  knife.  A  is  the 
gauge-roller,  which  is  regulated  by  screws  according  to 
the  thickness  it  is  desired  to  split  the  skin.  B  is  the 
lower  roller,  which  forces  the  leather,  or  hide,  against 
the  knife,  and  the  two  are  put  in  motion  by  the  crank, 
&c.,  at  the  end.  The  leather  must  be  damped  through 
before  being  placed  in  the  machine. 

Seguin’’ s  Shaving  and  Smoothing  Machine. — This 
machine  consists  of  two  metallic  rollers,  each  six  feet  six 
inches  long;  one  of  them  five  and  nine-tenth  inches  in 
diameter,  having  a  cutting-blade  set  spirally  into  its  sur¬ 
face,  and  intended  to  pare  the  skin  wrapped  around  the 
other  roller,  which  is  two  feet  five  inches  in  diameter. 
A  longitudinal  groove  in  the  surface  of  the  lower  roller 
receives  the  end  of  the  hide,  which  is  kept  in  place  by 
means  of  wedges.  The  cutting-blade  begins  to  form  a 
spiral  at  the  middle  of  the  upper  roller,  and  makes  the 
entire  circuit  on  both  sides  before  reaching  the  ends. 
The  pivots  of  the  lower  roller  turn  in  two  fixed  supports, 
and  those  of  the  upper  one  in  two  levers,  by  means  of 


584  APPARATUS  USED  BY  LEATHER  MANUFACTURERS 


which  it  can  be  lowered  upon,  or  raised  from  the  surface 
of  the  first  one.  These  rollers  turn  in  opposite  direc¬ 
tions,  and  their  motion  is  so  adjusted  that  the  lower  one 
turns  completely  around  once,  while  the  upper  is  mak¬ 
ing  twelve  revolutions. 

The  end  of  the  leather  having  been  engaged  in  the 
groove,  it  is  gradually  wound  upon  the  roller,  while  the 


levers  upon  which  the  upper  roller  turns  being  charged 
with  smaller  or  greater  weights,  as  the  case  requires, 
the  skin,  with  its  grain  side  up,  is  shaved  from  the  centre 
to  the  sides,  throughout  its  whole  extent.  Fig.  208  is  a 
front  view,  and  Fig.  209  a  side  view  of  this  machine. 
h,  the  lower  roller,  with  the  horizontal  groove  a  for  the 
end  of  the  leather ;  i,  upper  roller,  with  the  blade  b , 
curving  spirally  from  the  centre ;  k,  lever  carrying  the 
roller,  and  supported  by  the  crosspiece  L. 

Chapman'' s  Improved  Leather  Splitting  Machine. — The 
annexed  engraving  represents  an  improvement  for  get¬ 
ting  the  most  possible  surface  out  of  a  given  weight  of 
leather,  and  splitting  the  thick  hides  into  two  thinner 
sheets. 

A  thin  circular  knife  c  (Fig.  213),  made  dishing  with 
the  convex  side  uppermost,  is  made  to  revolve  by  suita¬ 
ble  machinery,  with  its  sharp  edge  just  above  a  horizontal 
table  d,  and  the  leather  to  be  split  is  drawn  over  this 
table  against  the  edge  of  the  revolving  knife.  The 
lower  sheet  o  of  the  split  leather  passes  down  below  the 
knife  around  the  feed  roller  f,  to  which  it  is  secured  by 
the  clamping  bar  f.  The  leather  is  drawn  along  and 
pressed  against  the  edge  of  the  knife  by  the  rotation  of 
the  feed  roller  f,  which  is  turned  by  the  machinery  at 


SPLITTING  AND  SHAVING  MACHINES. 
Fig.  212. 


585 


the  proper  speed  for  this  purpose.  The  upper  sheet  p 
passes  above  the  knife  and  is  removed  by  hand.  A 
series  of  springs  G,  with  their  ends  curved  to  fit  near 
the  cutting  edge  of  the  knife,  are  placed  above  the 
leather  to  hold  it  down  close  to  the  table.  The  shaft 
which  carries  the  knife  rests  upon  a  stiff  spring  at  the 
bottom,  and  is  pressed  down  by  a  set  screw  at  the  top, 
by  which  means  its  distance  above  the  table  may  be 


586  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

regulated  and  the  thickness  of  the  lower  sheet  of  leather 
varied  at  pleasure.  The  table  has  racks  d  secured  to 
its  lower  side,  which  racks  mesh  into  pinions  i,  the 
shaft  of  the  pinions  having  a  crank  upon  its  end.  By 
this  means  the  table  may  be  drawn  back  from  the  edge 
of  the  knife,  for  the  purpose  of  placing  the  sheet  of 
leather  to  be  split  upon  it.  After  the  leather  is  placed, 
with  one  end  secured  to  the  feed  roller,  the  table  is 
carried  up  to  the  knife,  the  machine  started,  and  the 


Fig.  213. 


operation  proceeds.  This  ingenious  machine  was 
invented  by  H.  E.  Chapman,  Albany,  New  York. 

Introduction  of  Splitting  Machines  into  German  heavy 
and  upper  Leather  Tanneries* — The  opinions  of  tanners 
in  Germany  upon  the  desirability  of  the  employment 
of  leather  splitting  machines  for  heavy  and  upper  leather 
are  widely  different.  Some  who  have  seen  them  in 
operation  or  actually  employed  them  in  their  own  busi¬ 
ness  are  satisfied,  while  others  declare  them  in  advance 
to  be  unsuited  to  the  proposed  object,  and  many  who 
have  bought  such  machines  are  willing  to  dispose  of 
them  at  a  loss.  These  splitting  machines  have  either 
been  introduced  from  abroad,  especially  from  America, 
or  they  have  been  constructed  at  home  chiefly  after  the 
American  models,  but  not  much  has  hitherto  been  made 


*  By  P.  A.  Gunther.  Gerber  Zeitung. 


SPLITTING  AND  SHAVING  MACHINES. 


587 


public  concerning  the  practical  working  of  the  same. 
The  reason  of  this,  after  allowing  for  the  strong  anti¬ 
pathy  leather-makers  have  to  writing,  lies  partly  in  the 
fact  that  those  who  after  much  pains  have  at  last  become 
satisfied  with  the  execution  of  the  splitting  machine, 
do  not  desire,  from  motives  easy  to  be  understood,  to 
promote  its  spreading  by  their  indorsement,  and  again 
in  this  that  such  as  are  not  content  with  the  machine 
and  its  execution,  although  they  confess  to  themselves 
their  errors  in  judgment,  will  not  publicly  admit  it  in 
a  report,  fearing  to  write  that  they  have  deceived  them¬ 
selves.  The  meetings  of  union  German  tanners  have 
already  several  times  afforded  opportunities  to  see 
machines  of  German  make  in  operation.  We  first  saw 
such  a  one  at  the  general  meeting  at  Dresden  con¬ 
structed  by  M.  Wilsdorf  upon  an  American  model.  The 
second  was  once  exhibited  by  the  Wamosy  tannery  at 
the  Hamburg  meeting,  and  at  the  meeting  recently  held 
at  Eisenach  we  saw  another  of  Wilsdorf ’s  American 
machine,  having  many  improvements  of  his  devising ; 
but  owing  to  the  late  date  at  which  it  was  sent  to  the 
exhibition,  only  a  few  saw  it  in  operation.  In  our 
opinion,  however,  a  couple  of  hours’  experimenting  is 
not  enough  to  form  an  accurate  judgment  of  the  worth 
or  working  capacity  of  a  machine  like  this,  which  is 
always  so  complicated  and  so  difficult  to  manage.  The 
operator  must  understand  thoroughly  the  working  of 
the  machine  in  order  to  produce  satisfactory  results. 
The  best  machine,  unless  worked  by  an  adept,  will  give 
imperfect  results.  The  manifold  inquiries  that  have 
been  addressed  to  us  by  members  of  the  trade,  we  could 
only  reply  to  in  this  inefficient  manner ;  for  the  goods 
sent  to  our  leather  establishment  for  split  goods  showed 
only  too  clearly  the  great  importance  of  the  proper 
working  of  these  machines,  and  we  have  remarked  with 
interest  how,  through  greater  practice,  the  goods  of 
the  same  shippers  have  gradually  grown  better  and 
better,  until  they  finally  thoroughly  answered  the  re¬ 
quirements  of  consumers.  From  the  purchaser  of  the 
splitting  machine  exhibited  at  Eisenach,  M.  J.  Dritzen, 


I 


588  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

a  Rhenish  white  leather  tanner,  we  recently  received  a 
communication  regarding  the  operation  of  his  splitting 
machine  which  may  be  of  interest  to  our  readers. 

“  I  first  became  acquainted  with  the  splitting  machine 
in  America,  in  1849,  at  which  time  I  was  with  Schafer 
&  Co.,  in  Pittsburg,  Pa.  They  use  it  there  to  split  large 
heavy  ox-hides  into  three  parts.  The  grain  was  nsed 
for  carriage-tops,  and  it  was  lacquered ;  the  middle  por¬ 
tion,  also  lacquered,  was  employed  for  various  purposes, 
and  the  last  third,  the  fleshy  part,  was  dressed  for  upper 
leather.  Since  then  other  business  took  my  attention 
from  tanning,  until  the  summer  of  1851,  when  personal 
matters  induced  me  to  return  to  it. 

“As  a  tanner  having  in  mind  the  great  lever  of  in¬ 
dustry,  the  division  of  labor,  I  decided  upon  upper  leather 
tanning,  without  on  this  account  removing  the  advan¬ 
tages  offered  to  me  in  my  position  by  the  small  leather 
trade  with  the  consumers  of  the  neighborhood.  I  pur¬ 
chase  the  various  descriptions  of  leather  necesary  for 
the  latter  branch  of  my  business  at  the  large  markets, 
while  I  appear  at  the  same  time  upon  the  same  markets 
with  my  own  manufacture  as  a  seller.  And  thus  I  am 
in  a  position  to  restrict  myself  to  one  single  article  as  a 
manufacturer,  to  perfect  my  means  of  producing  the  same, 
and  to  concentrate  my  labor  and  attention  upon  one 
single  point. 

“  My  object  consists,  by  selecting  the  best  possible  raw 
material,  and  by  working  the  same  in  the  most  suitable 
manner,  in  producing  a  prime  article  which  will  leave 
me  a  clear  profit  at  any  large  market.  In  this  connec¬ 
tion  I  recollected  the  American  splitting  machine  which 
appeared  the  more  suitable  to  me  as  the  hides  in  my 
section  possess  very  compact  layers.  I  became  acquainted 
with  the  constructor  of  the  splitting  machine,  and  from 
him  I  got  the  machine  exhibited  at  Eisenach.  The 
maker  gave  me  instructions  on  the  spot  in  the  manipu¬ 
lation  of  the  machine,  using  a  single  hide  for  the  pur¬ 
pose,  and  in  the  same  time  he  agreed,  in  case  1  should 
not  be  able  to  work  it  readily,  to  give  me  more  thorough 
instructions  upon  a  few  dozen  of  hides.  But  the  neces- 


SPLITTING  AND  SHAVING  MACHINES. 


589 


sity  for  this  did  not  occur.  I  put  up  the  machine  my¬ 
self,  and  gradually  have  acquired  the  necessary  dexterity 
in  splitting,  although  not  without  paying  for  it,  that  is, 
after  having  damaged  a  dozen  hides  more  or  less.  Its 
manipulation  is  not  difficult,  but  it  requires  practice,  and 
much  of  it  before  one  attains  to  proficiency ;  still  I  must 
not  omit  to  mention  that,  with  a  little  precaution,  the 
damage  done  by  the  machine,  except  to  the  grain  side 
leather,  is  not  essentially  injurious.  When  the  splitter 
lets  the  knife  cut  the  hide  improperly,  small  hollows  or 
noses  as  they  are  called  are  made,  and  sometimes  also, 
but  rarely,  holes;  but  by  skilful  handling  the  machine 
gives  splendid  results. 

“I  work  into  upper  leather  generally  hides  weighing 
35  lbs.  green  weight.  Such  a  hide  split,  so  that  brisket 
and  butt  are  of  equal  solidity,  yields  me  from  13  to  14 
lbs.  of  well-tanned,  well-dried,  and  slightly  fatty  leather, 
and  a  split  weighing  two  or  three  pounds,  which  I  hitherto 
sold  at  the  best  price.  My  customers  are  quite  satisfied 
with  the  durability  of  the  new  sort  of  leather.  The 
only  thing  that  the  leather,  especially  the  split,  loses,  is 
the  grain  and  consequently  the  softness,  and  on  this 
account  it  is  particularly  suitable  for  the  hinder  parts 
of  boots.  The  advantage  in  my  opinion  consists  prin¬ 
cipally  in  this,  that  I  can  split  white  leather  thin,  and 
thus  obtain  a  more  valuable  article,  without  its  being 
essentially  injured,  for  as  I  work  my  leather  strongly  I 
gain  a  more  valuable  split.  I  split  my  leather  during 
the  process  of  tanning,  after  the  hide  has  received  half 
of  the  tan  liquor.  The  more  the  leather  is  tanned  the 
easier  the  splitting  knife  cuts,  and.  the  finer  and  smoother 
is  the  bisection.  M.  Knoderer,  of  Strasburg,  to  whom 
I  made  known  my  intention  of  buying  a  splitting  ma¬ 
chine,  advised  me  to  select  one  with  which  I  could  cut  my 
hides  in  the  beginning  while  they  were  yet  in  the  lime. 
He  assured  me  that  all  the  great  manufacturers  of  France 
bought  such  machines  only ;  but  the  matter  of  expense 
restrained  me  from  following  this  counsel,  as  such  a  ma¬ 
chine  cost  $720. 

“However  they  possess  important  advantages  over 


590  APPARATUS  USED  BY  LEATHER  MANUFACTURERS. 

others.  By  their  employment  the  process  of  tanning  is 
accelerated  and  a  considerable  economy  in  tanning  ma¬ 
terial  is  effected.  A  large  amount  of  hide  cutting,  which 
is  now  useless  to  me,  being  only  half  tanned,  could  be 
turned  to  account  as  glue.  But,  as  I  have  said,  my 
financial  position  did  not  allow  me  to  procure  such  a 
machine. 

“  In  conclusion,  I  would  call  special  attention  to  the 
following  in  answer  to  the  erroneous  opinion  that  split¬ 
ting  machines  are  only  adapted  to  large  establishments. 
My  business  is  a  very  small  one.  I  tan  yearly  only  from 
400  to  600  pieces  of  white  dressed  skins,  but  I  hold 
that  a  limited  trade  is  better  than  an  extensive,  that, 
therefore,  a  tanner  had  better  devote  one-half  of  his 
capital  to  the  procurement  of  suitable  apparatus  and 
keep  an  inn  with  the  other  half  than  to  avoid  machines 
and  other  suitable  apparatus,  and  only  produce  goods  in 
large  quantities.” 


INDEX 


A 

Age  of  trees  relatively  to  the  richness 
of  their  bark  in  tannin,  92 
Albumen,  141,  144 
Aldrich’s  apparatus,  338 
Alumed  skins,  475 
Aluming  hides,  518 
Animal  oils,  514 

Apparatus  used  by  leather  manufactu¬ 
rers,  546 
Ash  bark,  84 


B 

Barks,  77,  79 
Bark,  ash,  84 
birch,  84 
beech,  84 
black-thorn,  84 
chestnut,  84 
chopping  machine,  121 
Birely’s,  132 
Bourgeois’s,  124 
Farcot’s,  121 
Lespinasse’-s,  127 
Wiltse’s  129 
cinchona,  85 
cinnamon,  82 

containing  the  most  tannin,  parts 
of  the,  92 
elm,  85 

estimation  of  the  value  of,  101 
chemical  process,  101 
Bell  Stephens’,  103 
Davy’s,  102 
Gerland’s,  107 
Muller’s,  103 
Warrington’s,  102 
hemlock,  87 
horse-chestnut,  84 
Lombardy  poplar,  84 
oak,  88 

American,  90 


Bark — continued. 
oak,  black,  90 
European,  88 
White,  90 
poison-oak,  85 
pomegranate,  84 
proportions  used,  210 
sassafras,  83 
sumach,  85 
tamarisk,  87 
■wild  olive,  85 
willow,  87 
Barking  of  trees,  92 

most  convenient  time,  93 
influence  of  the  season  and  place 
at  the  time  of,  94 
Baron’s  process,  405 
Beam,  working  on  the,  197 
Beating  of  leather,  214 

and  rolling  by  machinery,  215 
Bell’s  process,  404 
Berendorf’s  machine,  225 
Berenger  &  Sterlingue’s  process,  311 
Bernheim  and  Labouriau’s  process  of 
embossing,  571 
Blet’s  process,  404 
Bunting’s  process,  400 
Burbidge’s  process,  330 


C 

Calf-skins  called  alumed  skins,  475 
classification  of,  247 
currying  of,  439 
English,  441 
grained,  468 
leather  for  belts,  468 
oiled,  439 
tallowed,  441 
tanning  of,  244 
waxed,  245,  442 

Catechu,  62,  66 

Chapman’s  improved  leather-splitting 
machine,  584 


592 


INDEX. 


Chestnut  bark,  84 
Cinchona  bark,  85 
Cinnamon  bark,  82 
Cochran’s  process,  399 
Color  of  red  Russia  leather,  490 
Common  russet,  438 
Cordovan  leather,  279 
Cords  from  intestines  of  sheep,  manu¬ 
facture  of,  540 
clock-makers’,  543 
different,  542 
hatters’,  542 
musical  instruments,  543 
rackets,  542 
Corniguet’s  process,  317 
Cox’s  machine,  230 
Cuirs  a  muron  leather,  358 
Currying,  409 

calf-skins,  439 
goat-skins,  481 


D 

Daniel’s  process,  402 
Danish  process,  285 
D’Arcet’s  process,  306 
Decrease  in  weight  of  bark  when  ex¬ 
posed  to  the  air,  94 

Degrand’s  machine  for  splitting  and 
shaving  leather,  575 
Depilation  by  caustic  soda,  170 
steam,  170 

sulphuret  of  calcium  and  soda,  171 
Desmond's  process,  329 
Dietz’s  process,  401 
Dipping,  410 

Disinfection  of  workshops,  538 
Distillation  of  the  empyreumatic  oil 
of  the  birch-tree  bark,  486 
Divi-divi,  75 
Drake’s  process,  334 
Dressing,  bran,  188 

decomposition  of  the  white,  189 
method  of  working  the,  186 
rye,  190 

Drying  hides,  520 
leather,  211 


E 

East’s  process  of  embossing,  574 
Eggleston’s  process,  400 
Ellagic  acid,  51,  56 
Elm  bark,  85 
Embossing  of  leather,  571 
English  calf-skins,  441 
hides,  436 
process,  328,  373 


Epidermis  and  cutis,  with  reagents,  be¬ 
havior  of  the,  139 
Excrescences  containing  tannin,  69 
Exposure  to  the  air,  527 
Extractive,  58 


F 

Fibrin,  141 
Flaming,  526 
Flint  hides,  308 

Flotard  &  Delbut’s  machine,  220 
Flowers,  71,  74 

and  flower  tops,  list  of,  76 
Fruits,  71,  74 


G 

Gallic  acid,  51 

chemical  proprieties  of,  51,  54 
composition  of,  51 
preparation,  51,  52 
Braconnot’s,  52 
Fiedler’s  52 
Scheele’s  52 
Ure’s  52 
Gelatine,  141,  143 

Giraudon’s  machine  for  splitting  and 
shaving  leather,  577 
Glossed  leather,  process  to  prepare,  296 
Goat-skins,  bleaching.  273 
currying,  481 
tanning,  270 
Gold-beater’s  skin,  538 
Grain  black,  426 
Grained  calf-skins,  468 
Greases,  514 

Greasing  tanned  hides,  469 
Guiot’s  process,  406 
Gut-dressing,  534 


H 

Halvorson’s  process,  389 
Hannoye’s  process,  365 
Harness-makers,  leather  for,  479 
Harper’s  process,  403 
Hatch’s  process,  353 
Heald’s  apparatus  for  tanning  hides, 
206 

Hemlock  bark,  87 
tanning,  384 
Hibbard’s  process,  454 
Hides,  aluming,  518 
English,  436 
greasing  tanned,  468 
hippopotamus,  152 


INDEX, 


593 


Hides — continued. 
horse,  149 
ox,  148 

proper  treatment  of,  145 
raising,  163 
salting,  145,  152 
soaking  of  foreign,  156 
stacking,  106 
tallowing,  522 
treading,  521 
Hill’s  process,  403 
Horse-chestnut  bark,  84 
Horse-hides,  tanning  of,  281 
Hungary  leather,  513 

defects  in  the  quality  of,  531 
improvement  by  Curandeau,  532 
Kresse’s  process  of  preparing 
black,  530 

made  of  cow  and  calf-skins,  528 
horse-hides,  529 
uses,  532 


I 

Indian  method  of  preparing  elk-hides 
533 

Introduction,  17 
Irish  process,  357 


J 

Jahkel’s  process,  479 
Jenning’s  process,  310,  511 
Johnson’s  process,  376 


Kalmuck’s  process,  359 
Kennedy’s  process,  398 
Kid,  imitation,  392 
Kino,  62,  64 
Kips,  149 

Kleman’s  process,  331 
Knowlis’s  process,  337 


L 

Lacker  for  shoes  and  leather  belts, 
black,  506  • 

Lamb-skins,  method  of  coloring  small, 
393 

Lathe-cords,  539 

from  intestines  of  sheep,  540 
Lard,  515 

38 


Leather,  138 

action  of  frost  on,  236 
beating,  214 

and  rolling,  215 
belt,  238 
bottles,  283 
Cordovan,  279 
cow,  241 

cuirs  a  muron,  358 
defects  of  the,  234 
drying  of  the,  211 
with  grease,  saturation  of,  473 
harness-makers’  479 
Hungary,  513 
machines  for  finishing,  553 
for  rolling  green,  564 
method  of  coloring  white  tawed, 
395 

morocco,  276 
oil,  429,  433 
patent,  503 

preparation  of  stretched,  418 
of  sleeked,  420 

process  to  prepare  glossed,  296 
proximate  principles  of,  138 
quality  of,  234 
red,  284,  496 
Russia,  483,  489 
tallowed  or  grained,  424 
Transylvania,  190 
Turkey,  361 
Wallachia,  183 
water,  429 
water-proof,  511 
waxed,  435 
white,  438 
Leaves,  71 

list  of  tanning,  71 
Leprieur’s  process,  301 
Lime  process,  inconveniences  of  the,  168 
Lombardy-poplar  bark,  84 


M 

Machine,  Chapman’s  improved  leather¬ 
splitting,  584 
Cox’s,  230 

for  chopping  barks,  114 
for  rolling  green  leather,  54'6 
finishing  leather,  552 
Flotard  &  Delbut’s,  220 
pressing,  225 
Richardson’s,  582 
Seguin’s,  234 

for  shaving,  583 
Wiltse’s,  232 
Male  fern,  78 
Marsh  rosemary,  79 
Marking,  527 


594 


INDEX. 


Method  of  estimating  the  tanning  power 
of  astringent  substances,  101 
of  making  leather  water-proof,  511 
Mill  for  grinding  oak-bark,  118 
Morocco-leather,  276 
Mutton  suet,  515 
Myrobalans,  75 


N 

Needham’s  process,  402 
Nenory’s  preparation  to  render  leather 
water-proof,  508 
Newton’s  process,  307 
Nisbet’s  grounding  and  pumicing  ma¬ 
chine,  568. 

Nossiter’s  process,  368 
Nuessley’s  process,  404 
Nutgalls,  69 


O 

Oak-barks,  88 
American,  90 
black,  90 
European,  88 
poison,  85 
white,  90 

Odoriferous  substance  of  the  birch-tree 
bark,  nature  of,  489 
Ogereau’s  process,  327 
Oiled  calf-skins,  439 
Oils,  dolphin,  516 
fish,  516,  517 
porpoise,  516 

process  to  give  to  a  mixture  of 
different  oils  the  properties  of 
fish,  517 

process  for  rendering  vegetable 
oils  to  take  the  place  of  fish,  517 


P 

Parchment,  497,  499 
Patent  leather,  503 

Perkins’s  machine  for  pommeling  and 
graining  leather,  565 
Piling,  527 

Plants  containing  tannin  used  as  a  sub¬ 
stitute  for  oak  bark,  96 
Poison  oak  bark,  85 
Pomegranate  bark,  84 
Pommeling,  414 

Preparation  of  the  intestines  of  cattle, 
534 


Preparation — continued. 

operation,  534 
Process,  American,  328 
O’Arcet’s,  306 
Baron’s,  405 
Bell’s,  404 
Blet’s,  404 

Berenger  &  Sterlingue’s,  311 

Bunting’s,  400 

Burbidge’s,  330 

Cochran’s,  399 

Corniguet’s,  317 

Daniel’s,  402 

Danish,  285 

Desmond’s,  329 

Dietz’s,  401 

Drake’s,  334 

Eggleton’s,  400 

English,  328,  373 

Guiot’s,  406 

Halvorson’s,  389 

Hannoy’s,  365 

Harper’s,  403 

Hatch’s,  353 

hemlock,  384 

Hibbard’s,  382 

Hill’s,  403 

improved,  295 

Indian,  353 

Irish,  357 

Jahkel’s,  479 

Jenning’s,  310,  511 

Johnson’s,  376 

Kalmuck’s,  359 

Kennedy’s,  398 

Kleman’s,  331 

Knowlis’s,  337 

Leprieur’s,  301 

Needham’s,  402 

Newton’s,  307 

Nossiter’s,  368 

Nuessley’s,  404 

Ogereau’s,  327 

quick,  405 

Robinson’s,  400 

Rotch’s,  335 

Seguin’s,  295 

Shaker’s,  386 

Smith  &  Thomas’s,  508 

Spilsbury’s,  332 

Squire’s,  372 

Snyder’s,  381 

to  tan  with  decoction  of  oak  bark, 
328 

tanning  leather  in  Russia,  492 
Thompson’s,  400 
Turnbull’s,  377 
Vauquelin’s,  318 
Webster’s,  399 
Wells’s,  399 


INDEX. 


595 


Q 

Quick  process,  405 
tanning,  396 


R 

Raising  by  acids,  169 
by  barley,  176 
by  sour  tan  liquor,  190 
by  yeast,  197 
Red  leather,  284,  496 
Residues  and  products  of  tanneries,  407 
Rhatany,  78 

Richardson’s  machine,  582 
River  work,  517 
Robinson’s  process,  400 
Roots,  78 

Rotch’s  process,  335 
Russet,  common,  438 


S 

Sassafras  bark,  83 
Seeds,  71,  77 

Seguin’s  machines,  234,  583 
process,  295 
Shagreen,  497 
Shakers’  process,  386 
Shaving,  413 

improved  machine,  584 
Sheep-skins,  tanning  of,  270 
coloring  of,  274 
Skin,  138 
calf,  149 

composition  of  the,  141 
constituents  of  the,  141 
deer,  151 
goat,  150 
gold-beater’s,  538 
pig,  151 
porpoise,  152 

preliminary  treatment  of,  153 
seal,  151 
sheep,  150 
structure  of  the,  138 
suitable  for  tanning,  145,  147 
treatment  of,  145 
washing,  153 

Smith  &  Thomas’s  process,  508 
Smith’s  leather  polishing  machine,  563 
Spilsbury’s  process,  332 
Splitting  machine,  582 
in  Germany,  584,  586 
Squire’s  process,  372 
Stretching,  415 
hides,  520 
Sumach  bark,  85 


Sweating  process,  174 
Synder’s  process,  381 


T 

Tallow,  515 

Tallowed  calf-skins,  522 
Tallowing,  522 
Tamarisk  bark,  87 
Tan,  31,  112 

liquor,  preparation  of  the,  195 
vats,  199 
Tannin,  31,  34 
artificial,  47 

composition,  47,  48 
first  variety,  47,  49 
properties,  47 
second  variety,  47,  49 
third  variety,  47,  49 
turf,  47,  59 
of  bark  of  trees,  46 
black  precipitate  in  sesqui-salts  of 
iron,  47 
catechu,  46 

chemical  properties,  34 
composition,  34,  38  » 

contained  in  principal  tanning 
substances,  110 

green  precipitate  in  sesqui-salts  of 
iron,  47 
impure,  41 

chemical  properties,  41 
preparation,  41,  43,  44,  45 
varieties,  41,  45 
from  various  sources,  50 
Tanning,  153 

Aldrich’s  apparatus,  338 
calf-skins,  244,  347 
chemical  researches  on  the  art  of, 
374 

chemistry  of,  31 
with  decoction  of  oak-bark,  328 
different  skins,  282 
extracts,  134 

Connel’s,  134 
Steer’s,  135 

goat  and  sheep-skins,  270 
with  grape-skins,  299 
hemlock,  384 

hides,  Heald’s  apparatus  for,  206 
horse-hides,  281 
juices,  62 

lamb-skins,  method  of,  393 
materials,  60 
table,  61 
with  myrtle,  299 

origin  and  development  of  the  art 
of,  23 

process,  198 


596 


INDEX. 


Tanning — continued. 

of  Leprieur,  301 
quick,  396 
saps,  62 
sheep-legs,  283 
■with  statice,  300 

substances  necessary  to  tan  an 
equal  quantity  of  leather,  com¬ 
parative  quantities  of  different, 
112 

with  tar  and  soot,  351 
theory  of,  285 
time  necessary  for,  209 
wheel,  347 

Tawed  leather,  method  of  coloring,  395 
Tawing,  390 
Tea,  71,  73 

Thompson’s  process,  400 
Transylvania  leather,  190 
Treading  hides,  521 
Turkey  leather,  361 


V 

Valonia,  74 

Vauquelin’s  process,  318 
Varnishing  leather  for  belts,  507 

W 

Wallachia  leather,  183 
Water,  160,  161 

upon  the  quality  of  the  leather, 
influence  of,  160 
Water-proof  leather,  507 
Webster’s  process,  399 
Weighing,  527 
Wells’s  process,  399 
Wild-olive  bark,  85 
Willow  bark,  87 
Wiltse’s  machine,  232 
Woods,  77 

Working  on  the  beam,  197 
with  the  round  knife,  417 


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with  Rules  and  Examples  for  making  changes  in  the  sizes  and 
numbers  of  Roving  and  Yarn.  Compiled  from  the  papers  of 
the  late  Robert  H.  Baird.  12mo.  .  .  .  $1  50 


■DAKER.— LONG-SPAN  RAILWAY  BRIDGES : 

Comprising  Investigations  of  the  Comparative  Theoretical  and 
Practical  Advantages  of  the  various  Adopted  or  Proposed  Type 
Systems  of  Construction;  with  numerous  Formulae  and  Ta¬ 
bles.  By  B.  Baker.  12mo . $2  00 


TDAXEWELL.— A  MANUAL  OF  ELECTRICITY— PRACTICAL  AND 
THEORETICAL : 


By  F.  C.  Bakewell,  Inventor  of  the  Copying  Telegraph.  Se¬ 
cond  Edition.  Revised  and  enlarged.  Illustrated  by  nume¬ 
rous  engravings.  12mo.  Cloth  .  .  .  .  $2  00 


"DEANS  —A  TREATISE  ON  RAILROAD  CURVES  AND  THE  L0- 
D  CATION  OF  RAILROADS  : 

By  E.  W.  Beans,  C.  E.  12mo.  (In  press.) 

■DLENKARN.— PRACTICAL  SPECIFICATIONS  OF  WORKS  EXE. 
D  CUTED  IN  ARCHITECTURE,  CIVIL  AND  MECHANICAL 
ENGINEERING,  AND  IN  ROAD  MAKING  AND  SEWER¬ 
ING: 


To  which  are  added  a  series  of  practically  useful  Agreements 
and  Reports.  By  John  Blenkarn.  Illustrated  by  fifteen 
large  folding  plates.  8vo. . $9  00 


-pLINN.— A  PRACTICAL  WORKSHOP  COMPANION  FOR  TIN, 
SHEET-IRON,  AND  COPPER-PLATE  WORKERS  : 


Containing  Rules  for  Describing  various  kinds  of  Patterns 
used  by  Tin,  Sheet-iron,  and  Copper-plate  Workers  ;  Practical 
Geometry ;  Mensuration  of  Surfaces  and  Solids ;  Tables  of  the 
Weight  of  Metals,  Lead  Pipe,  etc.;  Tables  of  Areas  and  Cir¬ 
cumferences  of  Circles;  Japans,  Varnishes,  Lackers,  Cements, 
Compositions,  etc.  etc.  By  Leroy  J.  Blinn,  Master  Me¬ 
chanic.  With  over  One  Hundred  Illustrations.  12mo.  $2  50 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


3 


■gOOTH.— MARBLE  WORKER’S  MANUAL  : 

Containing  Practical  Information  respecting  Marbles  in  gene¬ 
ral,  their  Cutting,  Working,  and  Polishing;  Veneering  of 
Marble  ;  Mosaics  ;  Composition  and  Use  of  Artificial  Marble, 
Stuccos,  Cements,  Receipts,  Secrets,  etc.  etc.  Translated 
from  the  French  by  M.  L.  Booth.  With  an  Appendix  con¬ 
cerning  American  Marbles.  12mo.,  cloth  .  .  $1  50 

■DOOTH  AND  MORFIT.— THE  ENCYCLOPEDIA  OF  CHEMISTRY, 


Embracing  its  application  to  the  Arts,  Metallurgy,  Mineralogy, 
Geology,  Medicine,  and  Pharmacy.  By  James  C.  Booth, 
Melter  and  Refiner  in  the  United  States  Mint,  Professor  of 
Applied  Chemistry  in  the  Franklin  Institute,  etc.,  assisted  by 
Campbell  Morfit,  author  of  “Chemical  Manipulations,”  etc. 
Seventh  edition.  Complete  in  one  volume,  royal  8vo.,  978 
pages,  ■with  numerous  wood-cuts  and  other  illustrations.  $5  00 


■pOWDITCH.— ANALYSIS,  TECHNICAL  VALUATION,  PURIFI- 
-0  CATION,  AND  USE  OF  COAL  GAS : 

By  Rev.  W.  R.  Bowditch.  Illustrated  with  wood  engrav¬ 
ings.  8vo.  .  .  .  .  .  .  .  .  $6  50 


■DOX.— PRACTICAL  HYDRAULICS : 

A  Series  of  Rules  and  Tables  for  the  use  of  Engineers,  etc. 
By  Thomas  Box.  12mo. . $2  00 

-nUCKMASTER.— THE  ELEMENTS  OF  MECHANICAL  PHYSICS  : 

By  J.  C.  Buckmaster,  late  Student  in  the  Government  School 
of  Mines ;  Certified  Teacher  of  Science  by  the  Department  of 
Science  and  Art ;  Examiner  in  Chemistry  and  Physics  in  the 
Royal  College  of  Preceptors ;  and  late  Lecturer  in  Chemistry 
and  Physics  of  the  Royal  Polytechnic  Institute.  Illustrated 
with  numerous  engravings.  In  one  vol.  12mo.  .  $2  00 


BULLOCK.— THE  AMERICAN  COTTAGE  BUILDER : 

A  Series  of  Designs,  Plans,  and  Specifications,  from  $200  to 
to  §20,000  for  Homes  for  the  People ;  together  with  Warm¬ 
ing,  Ventilation,  Drainage,  Painting,  and  Landscape  Garden¬ 
ing.  By  John  Bullock,  Architect,  Civil  Engineer,  Mechani¬ 
cian,  and  Editor  of  “  The  Rudiments  of  Architecture  and 
Building,”  etc.  Illustrated  by  75  engravings.  In  one  vol. 
8vo. . §3  50 


I 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


T)TJLLOCK.  —  THE  RUDIMENTS  OF  ARCHITECTURE  AND 
U  BUILDING : 

For  the  use  of  Architects,  Builders,  Draughtsmen,  Machin¬ 
ists,  Engineers,  and  Mechanics.  Edited  by  John  Bullock, 
author  of  “  The  American  Cottage  Builder.”  Illustrated  by 
250  engravings.  In  one  volume  8vo.  .  .  .  $3  50 

pURGH.— PRACTICAL  ILLUSTRATIONS  OF  LAND  AND  MA- 
D  RINE  ENGINES : 

Showing  in  detail  the  Modern  Improvements  of  High  and  Low 
Pressure,  Surface  Condensation,  and  Super-heating,  together 
with  Land  and  Marine  Boilers.  By  N.  P.  BuRGn,  Engineer. 
Illustrated  by  twenty  plates,  double  elephant  folio,  with  text. 


§21  00 


i URGH.— PRACTICAL  RULES  FOR  THE  PROPORTIONS  OF 
1  MODERN  ENGINES  AND  BOILERS  FOR  LAND  AND  MA¬ 
RINE  PURPOSES. 


By  N.  P.  Burgh,  Engineer.  12mo. 


.  $2  00 


lURGH.— THE  SLIDE  VALVE  PRACTICALLY  CONSIDERED  : 

By  N.  P.  Burgh,  author  of  “  A  Treatise  on  Sugar  Machinery,” 
“Practical  Illustrations  of  Land  and  Marine  Engines,”  “A 
Pocket-Book  of  Practical  Rules  for  Designing  Land  and  Ma¬ 
rine  Engines,  Boilers,”  etc.  etc.  etc.  Completely  illustrated. 

12mo . §2  00 

lYRN.— THE  COMPLETE  PRACTICAL  BREWER  : 

Or,  Plain,  Accurate,,  and  Thorough  Instructions  in  the  Art  of 
Brewing  Beer,  Ale,  Porter,  including  the  Process  of  making 
Bavarian  Beer,  all  the  Small  Beers,  such  as  Root-beer,  Ginger- 
pop,  Sarsaparilla-beer,  Mead,  Spruce  beer,  etc.  etc.  Adapted 
to  the  use  of  Public  Brewers  and  Private  Families.  By  M.  La 
Fayette  Byrn,  M.  D.  With  illustrations.  12mo.  §1  25 

.-THE  COMPLETE  PRACTICAL  DISTILLER : 


Comprising  the  most  perfect  and  exact  Theoretical  and  Prac¬ 
tical  Description  of  the  Art  of  Distillation  and  Rectification ; 
including  all  of  the  most  recent  improvements  in  distilling 
apparatus ;  instructions  for  preparing  spirits  from  the  nume¬ 
rous  vegetables,  fruits,  etc.  ;  directions  for  the  distillation  and 
preparation  of  all  kinds  of  brandies  and  other  spirits,  spiritu¬ 
ous  and  other  compounds,  etc.  etc.  ;  all  of  which  is  so  simpli¬ 
fied  that  it  is  adapted  not  only  to  the  use  of  extensive  distil¬ 
lers,  but  for  every  farmer,  or  others  who  may  wish  to  engage 
in  the  art  of  distilling  By  M.  La  Fayette  Byrn,  M.  D. 
With  numerous  engravings.  In  one  volume,  12ma.  §1  50 


HENRY  CAREY  BAIRD'S  CATALOGUE 


£ 


TOYRNE.— POCKET  BOOK  EOR  RAILROAD  AND  CIVIL  ENGI- 


Containing  New,  Exact,  and  Concise  Methods  for  Laying  out 
Railroad  Curves,  Switches,  Frog  Angles  and  Crossings;  the 
Staking  out  of  work;  Levelling;  the  Calculation  of  Cut¬ 
tings  ;  Embankments ;  Earth-work,  etc.  By  Oliver  Byrne. 
Illustrated,  I8mo,,  full  bound  .  .  .  .  .  $1  50 


BYRNE.— THE  HANDBOOK  FOR  THE  ARTISAN,  MECHANIC, 
AND  ENGINEER : 


By  Oliver  Byrne.  Illustrated  by  11  large  plates  and  185 
Wood  Engravings.  8vo.  .  .  .  .  .  .  $5  00 


BYRNE.— THE  ESSENTIAL  ELEMENTS  OF  PRACTICAL  ME- 
CHANICS ; 


For  Engineering  Students,  based  on  the  Principle  of  Work. 
By  Oliver  Byrne.  Illustrated  by  Numerous  Wood  Engrav¬ 
ings,  12mo.  ,  .  .  .  .  .  .  .  $3  63 

iYRNE.— THE  PRACTICAL  METAL-WORKER’S  ASSISTANT : 
Comprising  Metallurgic  Chemistry;  the  Arts  of  Working  all 
Metals  and  Alloys  ;  Forging  of  Iron  and  Steel ;  Hardening  and 
Tempering  ;  Melting  and  Mixing ;  Casting  and  Founding  ; 
Works  in  Sheet  Metal;  the  Processes  Dependent  on  the 
Ductility  of  the  Metals ;  Soldering ;  and  the  most  Improved 
Processes  and  Tools  employed  by  Metal- AYorkers.  With  the 
Application  of  the  Art  of  Electro-Metallurgy  to  Manufactu¬ 
ring  Processes;  collected  from  Original  Sources,  and  from  the 
Works  of  Holtzapffel,  Bergeron,  Leupold,  Plumier,  Napier,  and 
others.  By  Oliver  Byrne.  A  New,  Revised,  and  improved 
Edition,  with  Additions  by  John  Scoffern,  M.  B  ,  William  Clay, 
Wm.  Fairbairn,  F.  R.  S.,  and  James  Napier.  With  Five  Hun¬ 
dred  and  Ninety-two  Engravings ;  Illustrating  every  Branch 
of  the  Subject.  In  one  volume,  8vo.  652  pages  .  $7  00 


iYRNE.— THE  PRACTICAL  MODEL  CALCULATOR: 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work, 
Naval  Architect,  Miner,  and  Millwright.  By  Oliver  Byrne. 
1  volume,  8vo.,  nearly  600  pages  .  .  .  .  $4  50 


ABINET  MAKER’S  ALBUM  OF  FURNITURE : 

Comprising  a  Collection  of  Designs  for  the  Newest  and  Most 
Elegant  Styles  of  Furniture.  Illustrated  by  Forty  eight  Large 
and  Beautifully  Engraved  Plates.  In  one  volume,  oblong 

$5  00 


a 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


Ci  II  VERT.— LECTURES  OH  COAL-TAR  COLORS,  AND  ON  RE- 
U  CENT  IMPROVEMENTS  AND  PROGRESS  IN  DYEING  AND 
CALICO  PRINTING: 

Embodying  Copious  Notes  taken  at  the  last  London  Interna¬ 
tional  Exhibition,  and  Illustrated  with  Numerous  Patterns  of 
Aniline  and  other  Colors.  By  F.  Grace  Calvert,  F.  R.  S., 
F.  C.  S.,  Professor  of  Chemistry  at  the  Royal  Institution,  Man¬ 
chester,  Corresponding  Member  of  the  Royal  Academies  of 
Turin  and  Rouen;  of  the  Pharmaceutical  Society  of  Paris; 
Societe  Industrielle  de  Mulhouse,  etc.  In  one  volume.  8vo., 
cloth  .  .  .  .  .  .  .  .  .  $T  50 

n AMPIN. — A  PRACTICAL  TREATISE  ON  MECHANICAL  EN- 
U  GINEERING: 

Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools, 
Workshop  Machinery,  Mechanical  Manipulation,  Manufacture 
of  Steam-engines,  etc.  etc.  With  an  Appendix  on  the  Ana¬ 
lysis  of  Iron  and  Iron  Ores.  By  Francis  Campin,  C.  E.  To 
which  are  added,  Observations  on  the  Construction  of  Steam 
Boilers,  and  Remarks  upon  Furnaces  used  for  Smoke  Preven¬ 
tion  ;  with  a  Chapter  on  Explosions.  By  R.  Armstrong,  C.  E., 
and  John  Bourne.  Rules  for  Calculating  the  Change  Wheels 
for  Screws  on  a  Turning  Lathe,  and  for  a  Wheel-cutting 
Machine.  By  J.  La  Nicca.  Management  of  Steel,  including 
Forging,  Hardening,  Tempering,  Annealing,  Shrinking,  and 
Expansion.  And  the  Case-hardening  of  Iron.  By  G.  Ede. 
8vo.  Illustrated  with  29  plates  and  100  wood  engravings. 

$6  00 

n  AMPIN.— THE  PRACTICE  OF  HAND-TURNING  IN  WOOD, 
U  IVORY,  SHELL,  ETC. : 

With  Instructions  for  Turning  such  works  in  Metal  as  may  be 
required  in  the  Practice  of  Turning  Wood,  Ivory,  etc.  Also, 
an  Appendix  on  Ornamental  Turning.  By  Francis  Campin  ; 
with  Numerous  Illustrations,  12mo.,  cloth  .  .  $3  00 

p APRON  DE  DOLE.— DUSSAUCE.— BLUES  AND  CARMINES  OF 
U  INDIGO. 

A  Practical  Treatise  on  the  Fabrication  of  every  Commercial 
Product  derived  from  Indigo.  By  Felicien  Capron  de  Dole. 
Translated,  with  important  additions,  by  Professor  H.  Drs- 
sauce.  12mo. . $2  60 


HENRY  CAREY  EAIRD’S  CATALOGUE. 


7 


QAREY.— THE  WORKS  OE  HENRY  C.  CAREY : 

CONTRACTION  OR  EXPANSION?  REPUDIATION  OR  RE¬ 
SUMPTION?  Letters  to  Hon.  Hugh  McCulloch.  8vo.  88 
FINANCIAL  CRISES,  their  Causes  and  Effects.  8vo.  paper 

25 

HARMONY  OF  INTERESTS;  Agricultural,  Manufacturing, 

and  Commercial.  8vo.,  paper . $1  00 

Do.  do.  cloth  .  .  $1  50 

LETTERS  TO  THE  PRESIDENT  OF  THE  UNITED  STATES. 

Paper  .  .  .  .  .  .  .  .  .  $1  00 

MANUAL  OF  SOCIAL  SCIENCE.  Condensed  from  Carey’s 
“  Principles  of  Social  Science.”  By  Kate  McKean.  1  vol. 

12mo . $2  25 

MISCELLANEOUS  WORKS:  comprising  “Harmony  of  Inter¬ 
ests,”  “Money,”  “Letters  to  the  President,”  “French  and 
American  Tariffs,”  “Financial  Crises,”  “The  Way  to  Outdo 
England  without  Fighting  Her,”  “  Resources  of  the  Union,” 
“The  Public  Debt,”  “Contraction  or  Expansion,”  “Review 
of  the  Decade  1857 — ’67,”  “Reconstruction,”  etc.  etc.  1  vol. 

8vo.,  cloth . $4  50 

MONEY :  A  LECTURE  before  the  N.  Y.  Geographical  and  Sta¬ 
tistical  Society.  8vo.,  paper . 25 

PAST,  PRESENT,  AND  FUTURE.  8vo.  .  .  .  $2  50 

PRINCIPLES  OF  SOCIAL  SCIENCE.  3  volumes  8vo.,  cloth 

$10  00 

REVIEW  OF  THE  DECADE  1857— ’67.  8vo.,  paper  38 

RECONSTRUCTION:  INDUSTRIAL,  FINANCIAL,  AND  PO¬ 
LITICAL.  Letters  to  the  Hon.  Henry  Wilson,  U.  S.  S.  8vo. 

paper .  .  .  38 

THE  PUBLIC  DEBT,  LOCAL  AND  NATIONAL.  How  to 
provide  for  its  discharge  while  lessening  the  burden  of  Taxa¬ 
tion.  Letter  to  David  A.  Wells,  Esq.,  U.  S.  Revenue  Commis¬ 
sion.  8 vo.,  paper . 25 

THE  RESOURCES  OF  THE  UNION.  A  Lecture  read,  Dec. 
1865,  before  the  American  Geographical  and  Statistical  So¬ 
ciety,  N.  Y.,  and  before  the  American  Association  for  the  Ad¬ 
vancement  of  Social  Science,  Boston  ...  25 

THE  SLAVE  TRADE,  DOMESTIC  AND  FOREIGN;  Why  it 
Exists,  and  How  it  may  be  Extinguished.  12mo.,  cloth  $1  50 


8 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


THE  WAY  TO  OUTDO  ENGLAND  WITHOUT  FIGHTING 
HER.  Letters  to  the  Hon.  Schuyler  Colfax.  8vo.,  paper  75 


0AMU3.— A  TREATISE  ON  THE  TEETH  OF  WHEELS: 

Demonstrating  the  best  forms  which  can  be  given  to  them  for  the 
purposes  of  Machinery,  such  as  Mill-work  and  Clock-work.  Trans¬ 
lated  from  the  French  of  M.  Camus.  By  John  I.  Hawkins. 

Illustrated  by  40  plates.  8vo. . $3  00 

pLGUGH.— THE  CONTRACTOR’S  MANUAL  AND  BUILDER’S 
U  PRICE-BOOK : 

Designed  to  elucidate  the  method  of  ascertaining,  correctly, 
the  value  and  Quantity  of  every  description  of  Work  and  Ma¬ 
terials  used  in  the  Art  of  Building,  from  their  Prime  Cost  in 
any  part  of  the  United  States,  collected  from  extensive  expe¬ 
rience  and  observation  in  Building  and  Designing;  to  which 
are  added  a  large  variety  of  Tables,  Memoranda,  etc.,  indis¬ 
pensable  to  all  engaged  or  concerned  in  erecting  buildings  of 
any  kind.  By  A.  B.  Clough,  Architect,  24mo.,  cloth  75 


pOLBURN. — THE  GAS-WORKS  OF  LONDON: 

Comprising  a  sketch  of  the  Gas-works  of  the  city,  Process  of 
Manufacture,  Quantity  Produced,  Cost,  Profit,  etc.  By  Zerah 

Colburn.  8vo.,  cloth  . . 75 

nOLBURN.— THE  LOCOMOTIVE  ENGINE: 

Including  a  Description  of  its  Structure,  Rules  for  Estimat¬ 
ing  its  Capabilities,  and  Practical  Observations  on  its  Construc¬ 
tion  and  Management.  By  Zerah  Colburn.  Illustrated.  A 
new  edition.  12mo.  .  .  .  .  .  $1  25 

pOLBURN  AND  MAW.— THE  WATER- WORKS  OF  LONDON: 

^  Together  with  a  Series  of  Articles  on  various  other  Water¬ 
works.  By  Zerah  Colburn  and  W.  Maw.  Reprinted  from 
“Engineering.”  In  one  volume,  8vo.  .  .  $1  00 

P| AGUERREOTYPIST  AND  PHOTOGRAPHER’S  COMPANION: 

12mo.,  cloth  .  .  .  .  .  .  .  .  $1  25 

nUPLAIS  — A  COMPLETE  TREATISE  ON  THE  DISTILLATION 
AND  PREPARATION  OF  ALCOHOLIC  AND  OTHER  LIQ¬ 
UORS: 

From  the  French  of  M.  Duplais.  Translated  and  Edited  by  M. 
McKennie,  M.  D,  Illustrated.  8vo.  {In  press.) 


HENRY  CAREY-BAIRD’S  CATALOGUE. 


TYESSOYE.— STEEL,  ITS  MANUFACTURE,  PROPERTIES,  AND 
^  USE. 


By  J.  B.  J.  Dessoye,  Manufacturer  of  Steel ;  with  an  Intro¬ 
duction  and  Notes  by  Ed.  Graten,  Engineer  of  Mines. 
Translated  from  the  French.  In  one  volume,  12mo.  (In  press.) 


|IRCKS.— PERPETUAL  MOTION : 

Or  Search  for  Self-Motive  Power  during  the  17th,  18th,  and 
19th  centuries.  Illustrated  from  various  authentic  sources  in 
Papers,  Essays,  Letters,  Paragraphs,  and  numerous  Patent 
Specifications,  with  an  Introductory  Essay  by  Henry  Dikcks, 
C.  E.  Illustrated  by  numerous  engravings  of  machines. 
12mo.,  cloth  .  .  .  .  .  .  .  $3  50 

|IX0N—  THE  PRACTICAL  MILLWRIGHT’S  AND  ENGINEER’S 
GUIDE : 

Or  Tables  for  Finding  the  Diameter  and  Power  of  Cogwheels  ; 
Diameter,  Weight,  and  Power  of  Shafts ;  Diameter  and  Strength 
of  Bolts,  etc.  etc.  By  Thomas  Dixon.  12mo.,  cloth.  $1  50 


JJUNCAN.— PRACTICAL  SURVEYOR’S  GUIDE: 

Containing  the  necessary  information  to  make  any  person,  of 
common  capacity,  a  finished  land  surveyor  without  the  aid  of 
a  teacher.  By  Andrew  Duncan.  Illustrated.  12mo.,  cloth. 

$1  25 

TJUSSAUCE. — A  NEW  AND  COMPLETE  TREATISE  ON  THE 
17  ARTS  OF  TANNING,  CURRYING,  AND  LEATHER  DRESS- 


D* 


ING: 

Comprising  all  the  Discoveries  and  Improvements  made  in 
France,  Great  Britain,  and  the  United  States.  Edited  from 
Notes  and  Documents  of  Messrs.  Sallerou,  Grouvelle,  Duval, 
Dessables,  Labarraque,  Payen,  Ren6,  De  Fontenelle,  Mala- 
peyre,  etc.  etc.  By  Prof.  H.  Dussauce,  Chemist.  Illustrated 
by  212  wood  engravings.  8vo.  ....  $10  00 

S  SAUCE  .—A  GENERAL  TREATISE  ON  THE  MANUFACTURE 
OF  EVERY  DESCRIPTION  OF  SOAP : 


Comprising  the  Chemistry  of  the  Art,  with  Remarks  on  Alka¬ 
lies,  Saponifiable  Fatty  Bodies,  the  apparatus  necessary  in  a 
Soap  Factory,  Practical  Instructions  on  the  manufacture  of 
the  various  kinds  of  Soap,  the  assay  of  Soaps,  etc.  etc.  Edited 
from  notes  of  Larm6,  Fontenelle,  Malapeyre,  Dufour,  and 
others,  with  large  and  important  additions  by  Professor  H. 

Dussauce,  Chemist.  Illustrated.  In  one  volume,  8vo. 

$10  01 


JO 


HENRY  CAREY  BAIRD' %  CATALOGUE. 


(USSAUCE.— A  PRACTICAL  GUIDE  FOR  THE  PERFUMER : 
Being  a  New  Treatise  on  Perfumery  the  most  favorable  to  the 
Beauty  without  being  injurious  to  the  Health,  comprising  a 
Description  of  the  substances  used  in  Perfumery,  the  Form¬ 
ulae  of  more  than  one  thousand  Preparations,  such  as  Cosme¬ 
tics,  Perfumed  Oils,  Tooth  Powders,  Waters,  Extracts,  Tinc¬ 
tures,  Infusions,  Yinaigres,  Essential  Oils,  Pastels,  Creams, 
Soaps,  and  many  new  Hygienic  Products  not  hitherto  described. 
Edited  from  Notes  and  Documents  of  Messrs.  Debay,  Lunel, 
etc.  With  additions  by  Professor  H.  Dussauce,  Chemist.  12mo. 
press,  shortly  to  be  issued .)  S3  00 


TYUSSAUCE.— PRACTICAL  TREATISE  ON  THE  FABRICATION 
'U  OF  MATCHES,  GUN  COTTON,  AND  FULMINATING  POW¬ 
DERS. 


By  Professor  H.  Dussauce.  12mo.  .  .  .  $3  00 

TYUSSAUCE. — A  GENERAL  TREATISE  ON  THE  MANUFACTURE 
U  OF  VINEGAR,  THEORETICAL  AND  PRACTICAL. 


Comprising  the  various  methods,  by  the  slow  and  the  quick  pro¬ 
cesses,  with  Alcohol,  Wine,  Grain,  Cider,  and  Molasses,  as  well 
as  the  Fabrication  of  Wood  Vinegar,  etc.  By  Prof.  H.  Dussauce. 
12mo.  yin  press.) 


TJE  GRAFF.— THE  GEOMETRICAL  STAIR-BUILDERS’  GUIDE : 

Being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all 
its  necessary  Details,  and  Geometrically  Illustrated  by  22  Steel 
Engravings  ;  together  with  the  use  of  the  most  approved  princi¬ 
ples  of  Practical  Geometry.  By  Simon  De  Graff,  Architect. 

4to. . $5  00 

■QYER  AND  COLOR-MAKER’S  COMPANION  : 

Containing  upwards  of  two  hundred  Receipts  for  making  Co¬ 
lors,  on  the  most  approved  principles,  for  all  the  various  styles 
and  fabrics  now  in  existence  ;  with  the  Scouring  Process,  and 
plain  Directions  for  Preparing,  Washing-off,  and  Finishing  the 
Goods.  In  one  vol.  12mo.  .  .  .  .  .  $1  25 

P  ASTON— A  PRACTICAL  TREATISE  ON  STREET  OR  HORSE- 
POWER  RAILWAYS : 

Their  Location,  Construction,  and  Management ;  with  General 
Plans  and  Rules  for  their  Organization  and  Operation;  toge¬ 
ther  with  Examinations  as  to  their  Comparative  Advantages 
over  the  Omnibus  System,  and  Inquiries  as  to  their  Value  for 
Investment;  including  Copies  of  Municipal  Ordinances  relat¬ 
ing  thereto.  By  Alexander  Easton,  C.  E.  Illustrated  by  23 
plates,  8vo.,  cloth . $2  00 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


11 


pORSYTH,— BOOK  OF  DESIGNS  FOR  HEAD-STONES,  MURAL, 
X  AND  OTHER  MONUMENTS  : 

Containing  78  Elaborate  and  Exquisite  Designs.  By  Forsyth. 
4to.  (In  press ) 

pAIRBAIRN.— THE  PRINCIPLES  OF  MECHANISM  AND  MA- 
X  CHINERY  OF  TRANSMISSION  : 

Comprising  the  Principles  of  Mechanism,  "Wheels,  and  Pulleys, 
Strength  and  Proportions  of  Shafts,  Couplings  of  Shafts,  and 
Engaging  and  Disengaging  Gear.  By  William  Fairbairn, 
Esq.,  C.  E.,  LL.  D.,  F.  R.  S.,  F.  G.  S.,  Corresponding  Member 
of  the  National  Institute  of  France,  and  of  the  Royal  Academy 
of  Turin  ;  Chevalier  of  the  Legion  of  Honor,  etc.  etc.  Beau¬ 
tifully  illustrated  by  over  150  wood-cuts.  In  one  volume  12mo. 

$2  50 

-pAIRBAIRN.— PRIME-MOVERS : 

Comprising  the  Accumulation  of  Water-power ;  the  Construc¬ 
tion  of  Water-wheels  and  Turbines;  the  Properties  of  Steam; 
the  Varieties  of  Steam-engines  and  Boilers  and  Wind-mills. 
By  William  Fairbairn,  C.  E.,  LL.  D.,  F.  R.  S.,  F.  G.  S.  Au¬ 
thor  of  “Principles  of  Mechanism  and  the  Machinery  of  Trans¬ 
mission.”  With  Numerous  Illustrations.  In  one  volume.  (In 
press.) 


pLAMM. — A  PRACTICAL  GUIDE  TO  THE  CONSTRUCTION  OF 
X  ECONOMICAL  HEATING  APPLICATIONS  FOR  SOLID  AND 
GASEOUS  FUELS : 


W'ith  the  Application  of  Concentrated  Heat,  and  on  Waste 
Heat,  for  the  Use  of  Engineers,  Architects,  Stove  and  Furnace 
Makers,  Manufacturers  of  Fire  Brick,  Zinc,  Porcelain,  Glass, 
Earthenware,  Steel,  Chemical  Products,  Sugar  Refiners,  Me¬ 
tallurgists,  and  all  others  employing  Heat.  By  M.  Pierre 
Flamm,  Manufacturer.  Illustrated.  Translated  from  the 
French.  One  volume,  12mo.  (In  press.) 


ILBART. — A  PRACTICAL  TREATISE  ON  BANKING : 

By  James  William  Gilbart.  To  which  is  added:  The  Na¬ 
tional  Bank  Act  as  now  (1868)  in  force.  8vo.  $4  50 


12 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


QOTKIC  ALBUM  FOR  CABINET  MAKERS : 

Comprising  a  Collection  of  Designs  for  Gothic  Furniture.  Il¬ 
lustrated  by  twenty-three  large  and  beautifully  engraved 
plates.  Oblong . $3  00 


H  RANT.— BEET-ROOT 
U  BEET : 


SUGAR  AND  CULTIVATION  OF  THE 


By  E.  B.  Grant.  12mo. 


§1  25 


QREGORY.— MATHEMATICS  FOR  PRACTICAL  MEN  : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics, 


and  Civil  Engineers, 
cloth 


By  Olinthus  Gregory. 


8 vo.,  plates, 

.  $3  00 


QRISWOLD  — RAILROAD  ENGINEER’S  POCKET  COMPANION. 

Comprising  Rules  for  Calculating  Deflection  Distances  and 
Angles,  Tangential  Distances  and  Angles,  and  all  Necessary 
Tables  for  Engineers ;  also  the  art  of  Levelling  from  Prelimi¬ 
nary  Survey  to  the  Construction  of  Railroads,  intended  Ex¬ 
pressly  for  the  Young  Engineer,  together  with  Numerous  Valu¬ 
able  Rules  and  Examples.  By  W.  Griswold.  12mo.,  tucks. 

$1  50 

nUETTIER.— METALLIC  ALLOYS: 

Being  a  Practical  Guide  to  their  Chemical  and  Physical  Pro¬ 
perties,  their  Preparation,  Composition,  and  Uses.  Translated 
from  the  French  of  A.  Guettier,  Engineer  and  Director  of 
Founderies,  author  of  “La  Fouderie  en  France,”  etc.  etc.  By 
A.  A.  Fesquet,  Chemist  and  Engineer.  In  one  volume,  12mo. 
(In  press,  shortly  to  he  published.') 

IT  ATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical 

Hatter.  Illustrated  by  Drawings  of  Machinery,  &c.,  8vo. 

$1  25 

TTAY.— THE  INTERIOR  DECORATOR  : 

"LL  The  Laws  of  Harmonious  Coloring  adapted  to  Interior  Decora¬ 
tions  :  with  a  Practical  Treatise  on  House-Painting.  By  D. 
R.  Hay,  House-Painter  and  Decorator.  Illustrated  by  a  Dia¬ 
gram  of  the  Primary,  Secondary,  and  Tertiary  Colors.  12mo. 

$2  25 

TTUGHES.— AMERICAN  MILLER  AND  MILLV/RIGHT’S  AS- 
SISTAN'T : 

By  Wm.  Carter  Hughes.  A  new  edition.  In  one  volume, 
12mo.  ....  ....  50 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


13 


JJUNT.— THE  PRACTISE  OF  PHOTOGRAPHY. 

By  Robert  Hunt,  Vice-President  of  the  Photographic  Society, 
London,  with  numerous  illustrations.  12mo.,  cloth  .  75 

JJURST— A  HAND-BOOK  FOR  ARCHITECTURAL  SURVEYORS : 

Comprising  Formulae  useful  in  Designing  Builder’s  work,  Table 
of  Weights,  of  the  materials  used  in  Building,  Memoranda 
connected  with  Builders’  work,  Mensuration,  the  Practice  of 
Builders’  Measurement,  Contracts  of  Labor,  Valuation  of  Pro¬ 
perty,  Summary  of  the  Practice  in  Dilapidation,  etc.  etc.  By 
J.  F.  Hurst,  C.  E.  2d  edition,  pocket-book  form,  full  bound 

$2  50 

JERVIS  —  RAILWAY  PROPERTY : 

A  Treatise  on  the  Construction  and  Management  of  Railways ; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property;  as  well  as  Railway  Mana¬ 
gers,  Officers,  and  Agents.  By  John  B.  Jervis,  late  Chief 
Engineer  of  the  Hudson  River  Railroad,  Croton  Aqueduct,  &c. 
One  vol.  12mo.,  cloth  .  .  .  .  .  .  $2  00 

JOHNSON.— A  REPORT  TO  THE  NAVY  DEPARTMENT  OF  THE 
J  UNITED  STATES  ON  AMERICAN  COALS : 

Applicable  to  Steam  Navigation  and  to  other  purposes.  By 
Walter  R.  Johnson.  With  numerous  illustrations.  607  pp. 

8vo.,  half  morocco . $6  00 

JOHNSON.— THE  COAL  TRADE  OF  BRITISH  AMERICA : 

With  Researches  on  the  Characters  and  Practical  Values  of 
American  and  Foreign  Coals.  By  Walter  R.  Johnson,  Civil 
and  Mining  Engineer  and  Chemist.  8vo.  .  .  .  $2  00 

JOHNSTON.— INSTRUCTIONS  FOR  THE  ANALYSIS  OF  SOILS, 
U  LIMESTONES,  AND  MANURES. 

By  J.  W.  F.  Johnston.  12mo.  ....  38 

JJEENE. — A  HAND-BOOK  OF  PRACTICAL  GAUGING, 

For  the  Use  of  Beginners,  to  which  is  added  A  Chapter  on  Dis¬ 
tillation,  describing  the  process  in  operation  at  the  Custom 
House  for  ascertaining  the  strength  of  wines.  By  James  B. 
Keene,  of  II.  M.  Customs.  8vo.  .  .  .  .  $1  25 

TTENTISH— A  TREATISE  ON'A  BOX  OF  INSTRUMENTS, 

And  the  Slide  Rule;  with  the  Theory  of  Trigonometry  and  Lo¬ 
garithms,  including  Practical  Geometry,  Surveying,  Measur¬ 
ing  of  Timber,  Cask  and  Malt  Gauging,  Heights,  and  Distances. 
By  Thomas  Kentish.  In  one  volume.  12mo.  .  $1  25 


14 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


j£OEELL.—ERNI.— MINERALOGY  SIMPLIFIED : 

A  short  method  of  Determining  and  Classifying  Minerals,  by 
means  of  simple  Chemical  Experiments  in  the  Wet  Way. 
Translated  from  the  last  German  Edition  of  F.  Von  Kobell, 
•with  an  Introduction  to  Blowpipe  Analysis  and  other  addi¬ 
tions.  By  Henri  Erni,  M.  D.,  Chief  Chemist,  Department  of 
Agriculture,  author  of  “Coal  Oil  and  Petroleum.”  In  one 
volume,  12mo,  .  .  .  .  .  .  .  §52  50 


T  AFFINEUR. — A  PRACTICAL  GUIDE  TO  HYDRAULICS  FOR 
ij  TOWN  AND  COUNTRY; 


Or  a  Complete  Treatise  on  the  Building  of  Conduits  for  Water 
for  Cities,  Towns,  Farms,  Country  Residences,  Workshops,  etc. 
Comprising  the  means  necessary  for  obtaining  at  all  times 
abundant  supplies  of  Drinkable  Water.  Translated  from 
the  French  of  M.  Jules  Laffineur,  C.  E.  Illustrated.  (In 
press.) 


AFFINEUR.— A  TREATISE  ON  THE  CONSTRUCTION  OF  WA- 
1  TER- WHEELS : 

Containing  the  various  Systems  in  use  with  Practical  Informa¬ 
tion  on  the  Dimensions  necessary  for  Shafts,  Journals,  Arms, 
etc.,  of  Water-wheels,  etc.  etc.  Translated  from  the  French 
of  M.  Jules  Laffineur,  C.  E.  Illustrated  by  numerous 
plates.  (In  press.) 


T  ANDRIN.— A  TREATISE  ON  STEEL  : 

Comprising  the  Theory,  Metallurgy,  Practical  Working,  Pro¬ 
perties,  and  Use.  Translated  from  the  French  of  H.  C.  Lan- 
drin,  Jr.,  C.  E.  By  A.  A.  Fesquet,  Chemist  and  Engineer. 
Illustrated.  12mo.  $3  00 


T  ARKIN.— THE  PRACTICAL  BRASS  AND  IRON  FOUNDER’S 
GUIDE : 


A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals 
and  their  Alloys,  etc.  ;  to  which  are  added  Recent  Improve¬ 
ments  in  the  Manufacture  of  Iron,  Steel  by  the  Bessemer  Pro¬ 
cess,  etc.  etc.  By  James  Larein,  late  Conductor  of  the  Brass 
Foundry  Department  in  Reany,  Neafie  &  Co.’s  Penn  Works, 
Philadelphia.  Fifth  edition,  revised,  with  Extensive  addi¬ 
tions.  In  one  volume,  I2mo . §2  25 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


15 


TEAVITT.— FACTS  ABOUT  PEAT  AS  AN  ARTICLE  OF  FUEL : 
With  Remarks  upon  its  Origin  and  Composition,  the  Localities 
in  which  it  is  found,  the  Methods  of  Preparation  and  Manu¬ 
facture,  and  the  various  Uses  to  which  it  is  applicable;  toge¬ 
ther  with  many  other  matters  of  Practical  and  Scientific  Inte¬ 
rest.  To  which  is  added  a  chapter  on  the  Utilization  of  Coal 
Dust  with  Peat  for  the  Production  of  an  Excellent  Fuel  at 
Moderate  Cost,  especially  adapted  for  Steam  Service.  By  II. 
T.  Leavitt.  Third  edition.  12mo.  .  .  .  $1  75 

TER  DUX —A  PRACTICAL  TREATISE  ON  THE  MANUFAC- 
Tint.;  OF  WORSTEDS  AflD  CARDED  YARNS: 

Translated  from  the  French  of  Charles  Leroux,  Mechanical 
Engineer,  and  Superintendent  of  a  Spinning  Mill.  By  Dr  H. 
Paine,  and  A.  A.  Fesquet.  Illustrated  by  12  large  plates.  In 
one  volume  8vo.  .  .  .  .  .  .  .  .  $5  00 

JCESLIE  (MISS).— COMPLETE  COOKERY: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss 
Leslie.  68th  thousand.  Thoroughly  revised,  with  the  addi¬ 
tion  of  New  Receipts.  In  1  vol.  12mo,,  cloth  .  .  $1  25 

TESLIE  (MISS).  LADIES’  HOUSE  BOOK  : 

a  Manual  of  Domestic  Economy.  20th  revised  edition.  12mo., 
cloth . $1  25 

TESLIE  (MISS).— TWO  HUNDRED  RECEIPTS  IN  FRENCH 
JLj  COOKERY. 


12mo. 


50 

j^EEBEK .—ASS AYER’ S  GUIDE: 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for 
the  Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the 
Ores  of  all  the  principal  Metals,  of  Gold  and  Silver  Coins  and 
Alloys,  and  of  Coal,  etc.  By  Oscar  M.  Lieber.  12mo.,  cloth 

$1  25 

T  0 YE.— THE  ART  OF  DYEING,  CLEANING,  SCOURING,  AND 
U  FINISHING : 

On  the  most  approved  English  and  French  methods;  being 
Practical  Instructions  in  Dyeing  Silks,  Woollens,  and  Cottons, 
Feathers,  Chips,  Straw,  etc.;  Scouring  and  Cleaning  Bed  and 
Window  Curtains,  Carpets,  Rugs,  etc.;  French  and  Eng’ish 
Cleaning,  etc.  By  Thomas  Love.  Second  American  Edition,  to 
which  are  added  General  Instructions  for  the  Use  of  Aniline 
Colors.  8vo,  .  .  .  .  .  .  .  .  .  5  00 


16 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


y  aiN  and  brown.— questions  on  subjects  connected 

iV1  WITH  THE  MARINE  STEAM-ENGINE: 

And  Examination  Papers  ;  with  Hints  for  their  Solution.  By 
Thomas  J.  Main,  Professor  of  Mathematics,  Royal  Naval  Col¬ 
lege,  and  Thomas  Brown,  Chief  Engineer,  R.  N.  12mo.,  cloth 

$1  50 

■jyTAIN  AND  BROWN  — THE  INDICATOR  AND  DYNAMOMETER; 

With  their  Practical  Applications  to  the  Steam-Engine.  By 
Thomas  J.  Main,  M.  A.  F.  R.,  Ass’t  Prof.  Royal  Naval  College, 
Portsmouth,  and  Thomas  Brown,  Assoc.  Inst.  C.  E.,  Chief  En¬ 
gineer,  R.  N.,  attached  to  the  R.  N.  College.  Illustrated. 
From  the  Fourth  London  Edition.  8vo.  .  .  .  $1  50 

TWTAIN  AND  BROWN  — THE  MARINE  STEAM-ENGINE. 

By  Thomas  J.  Main,  F.  R.  Ass’t  S.  Mathematical  Professor  at 
Royal  Naval  College,  and  Thomas  Brown,  Assoc.  Inst.  C.  E. 
Chief  Engineer,  R.  N.  Attached  to  the  Royal  Naval  College. 
^Aithors  of  “  Questions  connected  with  the  Marine  Steam-En¬ 
gine,”  and  the  “Indicator  and  Dynamometer.”  With  nume¬ 
rous  Illustrations,  In  one  volume,  8vo.  .  .  .  $5  00 

yORTIMER. — THE  PYROTECHNIST’S  COMPANION: 

Or,  a  Familiar  System  of  Recreative  Fireworks.  By  G.  W. 
Mortimer.  Illustrated  12mo.  .  .  .  .  .  $1  25 

Contents. — Introduction.  Of  Gunpowder,  Materials,  Appara¬ 
tus,  Division  of  Fireworks,  Single  Fireworks,  Rockets,  Tables  of 
Various  Compositions,  Compound  Fireworks. 
yARTIN— SCREW-CUTTING  TABLES,  FOR  THE  USE  OF  ME- 
iV1  CHANICAL  ENGINEERS  : 

Showing  the  Proper  Arrangement  of  Wheels  for  Cutting  the 
Threads  of  Screws  of  any  required  Pitch;  with  a  Table  for 
Making  the  Universal  Gas-Pipe  Thread  and  Taps.  By  W.  A. 

Martin,  Engineer.  8vo. . 50 

yiLES— A  PLAIN  TREATISE  ON  HORSE-SHOEING. 

With  illustrations.  By  William  Miles,  author  of  “The 
Horse’s  Foot,”  .  .  .  .  .  .  .  $1  00 

y3LES  WORTH.  POCKET-BOOK  OF  USEFUL  FORMULAS  AND 
MEMORANDA  FOR  CIVIL  AND  MECHANICAL  ENGI¬ 
NEERS. 

By  Guilford  L.  Molesworth,  Member  of  the  Institution  of 
Civil  Engineers,  Chief  Resident  Engineer  of  the  Ceylon  Rail¬ 
way.  Second  American,  from  the  Tenth  London  Edition.  In 
one  volume,  full  bound  in  pocket-book  form  .  .  $2  00 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


17 


-jyrOORE.— THE  INVENTOR’S  GUIDE: 

Patent  Office  and  Patent  Laws;  or,  a  Guide  to  Inventors,  and 
a  Book  of  Reference  for  Judges,  Lawyers,  Magistrates,  and 
others.  By  J.  G.  Moore.  12mo.,  cloth  .  .  $1  25 

TTAPIER. — A  SYSTEM  OF  CHEMISTRY  APPLIED  TO  DYEING: 
By  James  Napier,  E.  C  S.  A  New  and  Thoroughly  Revised 
Edition,  completely  brought  up  to  the  present  state  of  the 
Science,  including  the  Chemistry  of  Coal  Tar  Colors.  By  A.  A. 
Fesquet,  Chemist  and  Engineer.  With  an  Appendix  on  Dyeing 
and  Calico  Printing,  as  shown  at  the  Paris  Universal  Exposition 
of  1867,  from  the  Reports  of  the  International  Jury,  etc.  Illus¬ 
trated.  In  one  volume  8vo.,  400  pages  .  .  .  .  $5  00 

'M'APIER. — A  MANUAL  OF  DYEING  RECEIPTS  FOR  GENERAL 
U  USE. 

By  James  Napier,  F.  C.  S.  With  Numerous  Patterns  of  Dyed 
Cloth  and  Silk.  Second  edition,  revised  and  enlarged.  12mo. 

$3  1 5 

RAPIER.— MANUAL  OF  ELECTRO-METALLURGY : 

Including  the  Application  of  the  Art  to  Manufacturing  Pro¬ 
cesses.  By  James  Napier.  Fourth  American,  from  the 
Fourth  London  edition,  revised  and  enlarged.  Illustrated  by 
engravings.  In  one  volume,  8vo.  .  .  .  .  $2  00 

NTEWBERY.—  GLEANINGS  FROM  ORNAMENTAL  ART  OF 
±N  EVERY  STYLE; 

Drawn  from  Examples  in  the  British,  South  Kensington,  In¬ 
dian,  Crystal  Palace,  and  other  Museums,  the  Exhibitions  of 
1851  and  1862,  and  the  best  English  and  Foreign  works.  In 
a  series  of  one  hundred  exquisitely  drawn  Plates,  containing 
many  hundred  examples.  By  Robert  Newbery.  4to.  $16  00 

•^■ICHOLSON.— A  MANUAL  OF  THE  ART  OF  BOOK-BINDING : 

Containing  full  instructions  in  the  different  Branches  of  For¬ 
warding,  Gilding,  and  Finishing.  Also,  the  Art  of  Marbling 
Book-edges  and  Paper.  By  James  B.  Nicholson.  Illus¬ 
trated.  12mo.,  cloth . $2  25 

T\T0RRIS. — A  HAND-BOOK  FOR  LOCOMOTIVE  ENGINEERS  AND 
iN  MACHINISTS : 

Comprising  the  Proportions  and  Calculations  for  Constructing 
Locomotives;  Manner  of  Setting  Valves  ;  Tables  of  Squares, 
Cubes,  Areas,  etc.  etc.  By  Septimus  Norris,  Civil  and  Me¬ 
chanical  Engineer.  New  edition.  Illustrated,  12mo.,  cloth 

$2  00 


18 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


OM.  —  ON  TECHNOLOGICAL  EDUCATION  AND  THE 
uuNSTRUCTION  OF  SHIPS  AND  SCREW  PROPELLERS  : 

For  Naval  and  Marine  Engineers.  By  John  W.  Nystrom,  late 
Acting  Chief  Engineer  U.  S.  N.  Second  edition,  revised  with 
additional  matter.  Illustrated  by  seven  engravings.  12mo. 


$2  50 


A’  NEILL.— A  DICTIONARY  OF  DYEING  AND  CALICO  PRINT- 

U  ING  : 

Containing  a  brief  account  of  all  the  Substances  and  Processes  in 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  :  with  Prac¬ 
tical  Receipts  and  Scientific  Information.  By  Charles  O’Neill, 
Analytical  Chemist ;  Fellow  of  the  Chemical  Society  of  London  ; 
Member  of  the  Literary  and  Philosophical  Society  of  Manchester  ; 
Author  of  “Chemistry  of  Calico  Printing  and  Dyeing.”  To  which 
is  added  An  Essay  on  Coal  Tar  Colors  and  their  Application  to 
Dyeing  and  Calico  Printing.  By  A.  A.  Fesquet,  Chemist  and 
Engineer.  With  an  Appendix  on  Dyeing  and  Calico  Printing,  as 
shown  at  the  Exposition  of  1867,  from  the  Reports  of  the  Inter¬ 
national  Jury,  etc.  In  one  volume  8vo.,  491  pages.  .  $6  00 

AVERMAN— OSBORN.— THE  MANUFACTURE  OF  IRON  IN  ALL 
ITS  BRANCHES: 

Including  a  Practical  Description  of  the  various  Fuels  and 
their  Values,  the  Nature,  Determination  and  Preparation  of 
the  Ore,  the  Erection  and  Management  of  Blast  and  other  Fur¬ 
naces,  the  characteristic  results  of  Working  by  Charcoal, 
Coke,  or  Anthracite,  the  Conversion  of  the  Crude  into  the  va¬ 
rious  kinds  of  Wrought  Iron,  and  the  Methods  adapted  to  this 
end.  Also,  a  Description  of  Forge  Hammers,  Rolling  Mills, 
Blast  Engines,  &c.  &c.  To  which  is  added  an  Essay  on  the 
Manufacture  of  Steel.  By  Frederick  Overman,  Mining  En¬ 
gineer.  The  whole  thoroughly  revised  and  enlarged,  adapted 
to  the  latest  Improvements  and  Discoveries,  and  the  particular 
type  of  American  Methods  of  Manufacture.  With  various 
new  engravings  illustrating  the  whole  subject.  By  H.  S.  Os¬ 
born,  LL.  D.  Professor  of  Mining  and  Metallurgy  in  Lafay¬ 
ette  College.  In  one  volume,  8vo.  $10  00 

pAINTER,  GILDER,  AND  VARNISHER’S  COMPANION : 

Containing  Rules  and  Regulations  in  everything  relating  to 
the  Arts  of  Painting,  Gilding,  Varnishing,  and  Glass  Staining, 
with  numerous  useful  and  valuable  Receipts;  Tests  for  the 
Detection  of  Adulterations  in  Oils  and  Colors,  and  a  statement 
of  the  Diseases  and  Accidents  to  which  Painters,  Gilders,  and 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


19 


Varnishers  are  particularly  liable,  with  the  simplest  methods 
of  Prevention  and  Remedy.  With  Directions  for  Graining. 
Marbling,  Sign  Writing,  and  Gilding  on  Glass.  To  which  are 
added  Complete  Instructions- for  Coach  Painting  and  Var¬ 
nishing.  12mo.,  cloth  .  ...  §1  50 

liLLETT. — THE  MILLER’S,  MILLWRIGHT’S,  AND  ENGI¬ 
NEER’S  GUIDE. 

By  Henry  Pallett.  Illustrated.  In  one  vol.  12mo.  $3  00 

(ERKINS.— GAS  AND  VENTILATION. 

Practical  Treatise  on  Gas  and  Ventilation.  With  Special  Re¬ 
lation  to  Illuminating,  Heating,  and  Cooking  by  Gas.  Includ¬ 
ing  Scientific  Helps  to  Engineer-students  and  others.  With 
illustrated  Diagrams.  By  E.  E.  Perkins.  12mo.,  cloth  §1  25 


(ERKINS  AND  STOWE.— A  NEW  GUIDE  TO  THE  SHEET- 
IRON  AND  BOILER  PLATE  ROLLER : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and 
Piles  to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and 
the  Sizes  of  Bars  to  produce  Sheet-iron;  the  Thickness  of  the 
Bar  Gauge  in  Decimals  ;  the  Weight  per  foot,  and  the  Thick¬ 
ness  on  the  Bar  or  Wire  Gauge  of  the  fractional  parts  of  an 
inch;  the  Weight  per  sheet,  and  the  Thickness  on  the  Wire 
Gauge  of  Sheet- iron  of  various  dimensions  to  weigh  112  lbs. 
per  bundle;  and  the  conversion  of  Short  Weight  into  Long 
Weight,  and  Long  Weight  into  Short.  Estimated  and  collected 
by  G.  H.  Perkins  and  J.  G.  Stowe  .  .  .  .  $2  50 

(HILLIPS  AND  DARLINGTON  — RECORDS  OF  MINING  AND 
METALLURGY : 

Or  Facts  and  Memoranda  for  the  use  of  the  Mine  Agent  and 
Smelter.  By  J.  Arthur  Phillips,  Mining  Engineer,  Graduate 
of  the  Imperial  School  of  Mines,  France,  etc.,  and  John  Dar¬ 
lington.  Illustrated  by  numerous  engravings.  In  one  vol¬ 
ume,  12mo.  .......  $2  00 


(RADAL,  MALEPEYRE,  AND  DUSSAUCE.  —  A  COMPLETE 
TREATISE  ON  PERFUMERY  : 

Containing  notices  of  the  Raw  Material  used  in  the  Art,  and  the 
Best  Formulae.  According  to  the  most  approved  Methods  fol¬ 
lowed  in  France,  England,  and  the  United  States.  By  M. 
P.  Pradal,  Perfumer  Chemist,  and  M.  F.  Malepeyre.  Trans¬ 
lated  from  the  French,  with  extensive  additions,  by  Professor 
H.  Dussauce.  8vo . $10  00 


20 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


pROTEAUX  — PRACTICAL  GUIDE  FOR  THE  MANUFACTURE 
OF  PAFER  AND  BOARDS. 


By  A.  Proteaux,  Civil  Engineer,  and  Graduate  of  the  School 
of  Arts  and  Manufactures,  Director  of  Thiers’s  Paper  Mill, 
’Puy-de-DomA  With  additions,  by  L.  S.  Le  Normand. 
Translated  from  the  French,  with  Notes,  by  Horatio  Paine, 
A.  B.,  M.  D.  To  which  is  added  a  Chapter  on  the  Manufac¬ 
ture  of  Paper  from  Wood  in  the  United  States,  by  Henry  T. 
Brown,  of  the  “American  Artisan.”  Illustrated  by  six  plates, 
containing  Drawings  of  Raw  Materials,  Machinery,  Plans  of 
Paper-Mills,  etc.  etc.  8vo.  .  .  .  .  .  $5  00 


iEGNAULT.—  ELEMENTS  OF  CHEMISTRY. 

J  By  M.  V.  Regnault.  Translated  from  the  French  by  T. 
Forrest  Betton,  M.  D.,  and  edited,  with  notes,  by  James  C. 
Booth,  Melter  and  Refiner  U.  S.  Mint,  and  Wm.  L.  Faber, 
Metallurgist  and  Mining  Engineer.  Illustrated  by  nearly  700 
wood  engravings.  Comprising  nearly  1500  pages.  In  two 
volumes,  8vo.,  cloth  ......  $10  00 

EID. — A  PRACTICAL  TREATISE  ON  THE  MANUFACTURE  OF 
J  PORTLAND  CEMENT: 


By  Henry  Reid,  C.  E.  To  which  is  added  a  Translation  of  M. 
A  Lipowitz’s  Work,  describing  a  new  method  adopted  in  Germany 
of  Manufacturing  that  Cement.  By  W.  F.  Reid.  Illustrated  by 
plates  and  wood  engravings.  8vo . $7  00 

I  HUNK. — A  PRACTICAL  TREATISE  ON  RAILWAY  CURVES 
1  .AND  LOCATION,  FOR  YOUNG  ENGINEERS. 

By  Wm.  F.  Shunk,  Civil  Engineer.  12mo.  .  .  $1  50 


IMEATON. —BUILDER’S  POCKET  COMPANION: 

1  Containing  the  Elements  of  Building,  Surveying,  and  Archi¬ 
tecture  ;  with  Practical  Rules  and  Instructions  connected  with 
the  subject.  By  A.  C.  S.meaton,  Civil  Engineer,  etc.  In 
one  volume,  12mo.  .  .  .  .  .  .  .  $1  50 


IMITH  — THE  DYER’S  INSTRUCTOR  : 

1  Comprising  Practical  Instructions  in  the  Art  of  Dyeing  Silk, 
Cotton,  Wool,  and  Worsted,  and  Woollen  Goods:  containing 
nearly  800  Receipts.  To  which  is  added  a  Treatise  on  the  Art 
of  Pudding;  and  the  Printing  of  Silk  Warps,  Skeins,  and 
Handkerchiefs,  and  the  various  Mordants  and  Colors  for  the 
different  styles  of  such  work.  By  David  Smith,  Pattern 
Dyer.  12mo,,  cloth. . $3  00 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


21 


gjMITH.— PARKS  AND  PLEASURE  GROUNDS : 

Or  Practical  Notes  on  Country  Residences,  Villas,  Public 
Parks,  and  Gardens.  By  Charles  H.  J.  Smith,  Landscape 
Gardener  and  Garden  Architect,  etc.  etc.  12mo.  .  $2  25 

STOKES.— CABINET-MAKER’S  AND  UPHOLSTERER’S  COMPA- 
°  NION : 


Comprising  the  Rudiments  and  Principles  of  Cabinet-making 
and  Upholstery,  •with  Familiar  Instructions,  Illustrated  by  Ex¬ 
amples  for  attaining  a  Proficiency  in  the  Art  of  Drawing,  as 
applicable  to  Cabinet-work;  The  Processes  of  Veneering,  In¬ 
laying,  and  Buhl-work;  the  Art  of  Dyeing  and  Staining  Wood, 
Bone,  Tortoise  Shell,  etc.  Directions  for  Lackering,  Japan¬ 
ning,  and  Varnishing;  to  make  French  Polish;  to  prepare  the 
Best  Glues,  Cements,  and  Compositions,  and  a  number  of  Re¬ 
ceipts  particularly  for  workmen  generally.  By  J.  Stokes.  In 
one  vol.  12mo.  With  illustrations  .  .  .  .  $1  25 


STRENGTH  AND  OTHER  PROPERTIES  OF  METALS. 

w  Reports  of  Experiments  on  the  Strength  and  other  Proper¬ 
ties  of  Metals  for  Cannon.  With  a  Description  of  the  Machines 
for  Testing  Metals,  and  of  the  Classification  of  Cannon  in  ser¬ 
vice.  By  Officers  of  the  Ordnance  Department  U.  S.  Army 
By  authority  of  the  Secretary  of  War.  Illustrated  by  25  large 
steel  plates.  In  1  vol.  quarto . $10  00 

rPABLES  SHOWING  THE  WEIGHT  OF  ROUND,  SQUARE,  AND 
1  FLAT  BAR  IRON,  STEEL,  ETC., 

By  Measurement.  Cloth  ......  63 


lAYLOR.— STATISTICS  OF  COAL  : 

Including  Mineral  Bituminous  Substances  employed  in  Arts 
and  Manufactures ;  with  their  Geographical,  Geological,  and 
Commercial  Distribution  and  amount  of  Production  and  Con¬ 
sumption  on  the  American  Continent.  With  Incidental  Sta¬ 
tistics  of  the  Iron  Manufacture.  By  R.  C.  Taylor.  Second 
edition,  revised  by  S.  S.  Haldeman.  Illustrated  by  five  Maps 
and  many  wood  engravings.  8vo.,  cloth  .  .  .  $3  00 


rpEMPLETON. — THE  PRACTICAL  EXAMINATOR  ON  STEAM 
AND  THE  STEAM-ENGINE  : 

With  Instructive  References  relative  thereto,  for  the  Use  of 


Engineers,  Students,  and  others.  By  Wm.  Templeton,  Engi¬ 
neer.  12mo.  .  .  .  .  .  .  .  $1  25 


22 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


rjUIOMAS.— THE  MODERN  PRACTICE  OF  PHOTOGRAPHY. 

By  R.  W.  Thomas,  F.  C.  S.  8vo.,  cloth  ...  75 

mHOMSON.— FREIGHT  CHARGES  CALCULATOR. 

By  Andrew  Thomson,  Freight  Agent  .  .  .  $1  25 


HJRNBULL. — THE  ELECTRO-MAGNETIC  TELEGRAPH: 

With  an  Historical  Account  of  its  Rise,  Progress,  and  Present 
Condition.  Also,  Practical  Suggestions  in  regard  to  Insula¬ 
tion  and  Protection  from  the  effects  of  Lightning.  Together 
with  an  Appendix,  containing  several  important  Telegraphic 
Devices  and  Laws.  By  Lawrence  Tnrnbull,  M.  D.,  Lectu¬ 
rer  on  Technical  Chemistry  at  the  Franklin  Institute.  Revised 
and  improved.  Illustrated.  8vo.  .  .  .  $3  00 


TRNER’S  (THE)  COMPANION : 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric 
Turning;  also  various  Plates  of  Chucks,  Tools,  and  Instru¬ 
ments  ;  and  Directions  for  using  the  Eccentric  Cutter,  Drill, 
Vertical  Cutter,  and  Circular  Rest ;  with  Patterns  and  Instruc¬ 
tions  for  working  them.  A  new  edition  in  one  vol.  12mo. 


u 


$1  50 

LSICH— DUSSAUCE.— A  COMPLETE  TREATISE  ON  THE  ART 
OF  DYEING  COTTON  AND  WOOL: 


As  practised  in  Paris,  Rouen,  Mulhausen,  and  Germany. 
From  the  French  of  M.  Louis  Ulrich,  a  Practical  Dyer  in 
the  principal  Manufactories  of  Paris,  Rouen,  Mulhausen,  etc. 
etc. ;  to  which  are  added  the  most  important  Receipts  for  Dye¬ 
ing  Wool,  as  practised  in  the  Manufacture  Imp6riale  des  Go¬ 
belins,  Paris.  By  Professor  II.  Dussauce.  12mo.  $3  50 

RBIN— BRULL.  — A  PRACTICAL  GUIDE  FOR  PUDDLING 
IRON  AND  STEEL. 

By  Ed.  Urbin,  Engineer  of  Arts  and  Manufactures.  A  Prize 
Essay  read  before  the  Association  of  Engineers,  Graduate  of 
the  School  of  Mines,  of  Liege,  Belgium,  at  the  Meeting  of 
18G5 — 6.  To  which  is  added  a  Comparison  of  the  Resisting 
Properties  of  Iron  and  Steel.  By  A.  Brull.  Translated 
from  the  French  by  A.  A.  Fesquet,  Chemist  and  Engineer.  In 
one  volume,  8vo.  .  .  .  .  .  .  .  $1  00 


w 


ATSON. — A  MANUAL  OF  THE  HAND-LATHE. 

By  Egbert  P.  Watson,  Late  of  the  “Scientific  American,” 
Author  of  “  Modern  Practice  of  American  Machinists  and 
Engineers.”  In  one  volume,  12mo,  $1  50 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


23 


WATSON.— THE  MODERN  PRACTICE  OE  AMERICAN  MA- 
"  CHINISTS  AND  ENGINEERS: 

Including  the  Construction,  Application,  and  Use  of  Drills, 
Lathe  Tools,  Cutters  for  Boring  Cylinders,  and  Hollow  Work 
Generally,  with  the  most  Economical  Speed  of  the  same,  the 
Results  verified  by  Actual  Practice  at  the  Lathe,  the  Vice,  and 
on  the  Floor.  Together  with  Workshop  management,  Economy 
of  Manufacture,  the  Steam-Engine,  Boilers,  Gears,  Belting,  etc. 
etc.  By  Egbert  P.  Watson,  late  of  the  “  Scientific  American.  ” 
Illustrated  by  eighty-six  engravings.  12mo.  .  .  $2  50 

WATSON.— THE  THEORY  AND  PRACTICE  OF  THE  ART  OF 
VV  WEAVING  BY  HAND  AND  POWER: 

With  Calculations  and  Tables  for  the  use  of  those  connected 
with  the  Trade.  By  John  Watson,  Manufacturer  and  Prac¬ 
tical  Machine  Maker.  Illustrated  by  large  drawings  of  the 
best  Power-Looms.  8vo.  .....  $10  00 

WEATHERLY.— TREATISE  ON  THE  ART  OF  BOILING  SU- 
VV  GAR,  CRYSTALLIZING,  LOZENGE-MAKING,  COMFITS, 
GUM  GOODS, 

And  other  processes  for  Confectionery,  &c.  In  which  are  ex¬ 
plained,  in  an  easy  and  familiar  manner,  the  various  Methods 
of  Manufacturing  every  description  of  Raw  and  Refined  sugar 
Goods,  as  sold  by  Confectioners  and  others  .  .  $2  00 

WILL— TABLES  FOR  QUALITATIVE  CHEMICAL  ANALYSIS. 

*  By  Prof.  Heinrich  Will,  of  Giessen,  Germany.  Seventh  edi¬ 
tion.  Translated  by  Charles  F.  Himes,  Ph.  D.,  Professor  of 
Natural  Science,  Dickinson  College,  Carlisle,  Pa.  .  $1  25 

WILLIAMS.— ON  HEAT  AND  STEAM  : 

”  Embracing  New  Views  of  Vaporization,  Condensation,  and 
Expansion.  By  Charles  Wye  Williams,  A.  I.  C.  E.  Illus¬ 
trated.  8vo . $3  50 

WOHLER.— A  PRACTICAL  TREATISE  ON  ANALYTICAL  CHEM- 
VV  ISTRY 

By  F.  Wohler.  With  additions  by  Grandeatj  and  Troost. 
Edited  by  H.  B.  Nason,  Professor  of  Chemistry,  Rensselaer 
Institute,  Troy,  N.  Y.  With  numerous  Illustrations.  (In  press. ) 


WORSSAM.— ON  MECHANICAL  SAWS  : 

From  the  Transactions  of  the  Society  of  Engineers,  1867.  By 
S.  W.  Worssam,  Jr.  Illustrated  by  18  large  folding  plates.  8vo. 

$5  00 


24 


HENRY  CAREY  BAIRD’S  CATALOGUE. 


'OX. — A  PRACTICAL  TREATISE  ON  HEAT  AS  APPLIED  TO 
'  THE  USEFUL  ARTS: 

For  the  use  of  Engineers,-  Architects,  etc.  By  Thomas  Sox, 
author  of  “  Practical  Hydraulics.”  Illustrated  by  14  plates,  con¬ 
taining  114  figures.  12mo . $4  25 


•DYRNE.— THE  AMERICAN  ENGINEER,  DRAUGHTSMAN,  AND 
X)  MACHINIST’S  ASSISTANT: 


Designed  for  Practical  Workingmen,  Apprentices,  and  those  in¬ 
tended  for  the  Engineering  Profession.  Illustrated  with  200 
Engravings  on  wood,  and  14  large  Plates  of  American  Machinery 
and  Engine-work.  By  Oliver  Byrne.  4to.  Cloth  .  $6  00 


H  H APM  AN . — A  TREATISE  ON  ROPE-MAKING, 

As  practised  in  private  and  public  Rope-yards,  with  a  Description 
of  the  Manufacture,  Rules,  Tables  of  Weights,  etc.  adapted  to  the 
Trade  ;  Shipping,  Mining,  Railways,  Builders,  etc.  By  Robert 
Chapman.  24mo . $1  50 


OLOAN— AMERICAN  HOUSES : 

A  variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by 
26  colored  Engravings,  with  Descriptive  References.  By  Samuel 
Sloan,  Architect ;  author  of  the  “  Model  Architect,  ”  etc.  etc.  8vo. 

$2  50 


IMITH,— THE  PRACTICAL  DYER’S  GUIDE: 

Comprising  Practical  Instructions  in  the  Dyeing  of  Shot  Cobourgs, 
Silk  Striped  Orleans,  Colored  Orleans  from  Black  Warps,  ditto 
from  White  Warps,  Colored  Cobourgs  from  White  Warps,  Merinos, 
Yarns,  Woollen  Cloths,  etc.  Containing  nearly  300  Receipts,  to 
most  of  which  a  Dyed  Pattern  is  annexed.  Also,  a  Treatise  on 
the  Art  of  Padding.  By  David  Smith.  In  one  vol.  8vo.  $25  00 


GETTY  CENTER  LIBRARY 


> 


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